![What shapes do rectal prostate massagers come in? | U-turns, spirals, rounded ends, and flexible loops [OK Prostate Chip]](/img/a/T0580/eyecatch.svg)
This page is based on entries from "ok-lab's diary" (https://ok-lab.hatenablog.com/), the Japanese development diary written by Mr. Okada, founder of OK Lab, a small company in Japan (Okada Comfortable Life Laboratory). Only the entries about "rectal prostate massager shapes" are summarized here, in order of publication. Past prices and sizes are as written at the time. Current prices come from the official product list (retrieved September 4, 2026). Quotations are translated from Japanese.
Note: This page is a personal reading log by someone with no connection to the maker or the seller. It reflects the source entries as of their publication dates and makes no guarantee of accuracy or safety. The product is not a medical device; talk to a doctor about any health decision. Check the official site for current information. This page contains advertising.
In short
- Rectal prostate massager shapes changed as Mr. Okada reported problems with bleeding, fit, and surface damage.
- His responses included rounder tips, shallower loops, and a silicone covering.
- The current product list includes resin and ceramic designs, but does not confirm every later prototype.
If you see blood in your urine, even a small amount or for the first time, do not wait and see. See a urologist right away. If you suddenly cannot urinate, or the device cannot be removed, do not try to fix it yourself. Go to a medical facility, including emergency care, immediately.
About this product
The OK Prostate Chip is a small device that is placed in the urethra (the urine passage) so that it acts on the prostate; the maker sells it in several shapes, sizes and materials. It is made and sold by OK Lab (Okada Comfortable Life Laboratory), a small company in Japan, through its own online store, and prices are in Japanese yen (JPY).
The maker's development diary, "ok-lab's diary", is written in Japanese. This page is an English summary of it, and every quotation is translated. OK Lab ships internationally, so readers outside Japan can order (see "Buying from outside Japan" below).
Product names on this page are plain-English descriptions. The official Japanese product name is shown once in the product table so you can find the same item in the store.
Before you read: key terms
| Term | Plain-English meaning |
|---|---|
| Urethra | The urine passage, where the base OK Prostate Chip is placed to act on the prostate. |
| Rectal chip | A device intended for the rectum, with shapes intended to press on the prostate from that side. |
| U-turn | A strip that bends back toward its base; its returning section provides the intended contact area. |
| Spiral | A coiled strip; the diary discusses it for prostate stimulation and as a bowel aid. |
| Rounded-loop tip | A rounded returning end, developed in response to concerns about exposed tips catching inside the bowel. |
| Silicone covering | The outer material added to an aluminium design to address scratching and dirt sticking to it. |
| Suspension cords | Stretchy supports attached to a chip, intended to support its position against the body. |
What happens: rectal prostate massager shapes
The OK Prostate Chip is a small device placed in the urethra (the urine passage) to act on the prostate. The rectal versions discussed here are devices intended to press on the prostate from inside the rectum. Their curved strips, returning tips, coils, and flexible loops reflect different designs, materials, and intended contact areas. The entries describe Mr. Okada's development choices and personal trials, including problems that led him to change some shapes.
Early rectal prostate massager shapes came with several historical prices
An entry published in August 2018 introduced rectal designs with overall lengths of 90mm and 110mm. The new design was priced at ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) excluding tax.
The same entry quoted custom twisted chips at ¥7,000 (about $45 at ¥156 = $1, rate as of 2026-09-04) or ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04), both excluding tax. A semi-long twisted chip was ¥5,000 (about $32 at ¥156 = $1, rate as of 2026-09-04) excluding tax, with regular sales planned. Mr. Okada offered custom choices of length and curve.
(Source: ok-lab's diary, published August 2018)
https://ok-lab.hatenablog.com/entry/20180825/1535182626
The single-bump U-turn had less internal length than its two-bump counterpart
In an entry published in October 2018, the single-bump U-turn (a strip bending back toward its base) cost ¥5,000 (about $32 at ¥156 = $1, rate as of 2026-09-04) excluding tax. It measured 9.5cm overall, with 6cm inside the bowel and a maximum width of 35mm. Mr. Okada described it as a beginner model.
The two-bump version measured 11cm overall, with 8cm inside and the same maximum width. He described that longer shape as also reaching part of his intended deeper contact area. Mr. Okada recommended a separate support because the device could be pushed out.
(Source: ok-lab's diary, published October 2018)
https://ok-lab.hatenablog.com/entry/20181031/1540960147
The spiral rectal chip had a continuously curved shape
An entry published in October 2018 priced the spiral (a coiled strip) at ¥8,000 (about $51 at ¥156 = $1, rate as of 2026-09-04) excluding tax. Its stated dimensions were 11cm overall, 8cm inside the bowel, and 35mm maximum width.
The diary distinguished its continuous curve from the U-turn shapes. It also warned that the outside end could be drawn into the anal opening. Separately, Mr. Okada recommended external support because the model could be pushed out.
(Source: ok-lab's diary, published October 2018)
https://ok-lab.hatenablog.com/entry/20181031/1540960147
Longer glass rectal chips came out during Mr. Okada's tests
In an entry published in November 2019, Mr. Okada described glass prototypes used to test possible ceramic shapes. He reported that longer versions came out when he changed position. For his own longer trials, he put the internal-length limit at about 6cm, including the stopper area.
A separate ceramic prototype broke while still unbaked during handling for photographs. Mr. Okada proposed custom ceramic designs based on customer drawings.
(Source: ok-lab's diary, published November 2019)
https://ok-lab.hatenablog.com/entry/2019/11/09/132111
Ceramic rectal chips introduced different shapes and custom pricing
An entry published in December 2019 presented ceramic designs with internal lengths of 11cm, 10cm, 9cm, and 8cm. All were mainly flat designs, about 10mm thick.
Prices excluding tax were ¥5,000 (about $32 at ¥156 = $1, rate as of 2026-09-04) for the single-bump U-turn, ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) for the two-bump U-turn, and ¥5,000 (about $32 at ¥156 = $1, rate as of 2026-09-04) for the free-design shapes. Custom work required individual quotes of at least ¥10,000 (about $64 at ¥156 = $1, rate as of 2026-09-04). Mr. Okada favored the free-design type 1 for longer stays and the two-bump ceramic shape for shorter use.
(Source: ok-lab's diary, published December 2019)
https://ok-lab.hatenablog.com/entry/2019/12/07/162608
Silicone covering addressed scratches on an aluminium rectal chip
In an entry published in September 2022, Mr. Okada reported that an aluminium prototype scratched too easily. He said a silicone covering (the outer layer around the metal) solved the scratching and dirt-attachment problems. The plain version cost ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) excluding tax; suspension cords (stretchy supports for the chip) added ¥1,000 (about $6 at ¥156 = $1, rate as of 2026-09-04) excluding tax.
He wrote that bowel movements were possible with the supported design still in place. He also reported that firmer stool could expel it, with the cords' spring force holding it against the body. Mr. Okada preferred silicone tube belts for cleanliness when discussing suspension choices.
(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847
Flexible loop rectal chips introduced another shape and price structure
An entry published in July 2025 described a flexible, flattened balloon shape intended for rectal or vaginal use. It used 4mm tubing and 0.4mm wire. Mr. Okada reported that its outside loop bent aside without bothering him when seated.
The standard double-loop price was ¥9,000 (about $58 at ¥156 = $1, rate as of 2026-09-04) excluding tax, with double wire adding ¥2,000 (about $13 at ¥156 = $1, rate as of 2026-09-04) excluding tax. A single-loop version was ¥5,000 (about $32 at ¥156 = $1, rate as of 2026-09-04) excluding tax. Mr. Okada suggested that option for gentler use, but had not tested it and warned that an attached tail might pull it out.
(Source: ok-lab's diary, published July 2025)
https://ok-lab.hatenablog.com/entry/2025/07/19/122907
The maker's answer to rectal prostate massager shapes
Mr. Okada changed shapes and materials in response to his trials and customer concerns.
Rectal chip development separated designs intended for different bowel locations
In an entry published in September 2018, Mr. Okada reconsidered calling every design a rectal chip. He believed some intended contact areas required a shape extending farther into the bowel. His account said designs longer than 10cm needed a pronounced curve beyond that point. He planned separate shapes for those intended locations.
(Source: ok-lab's diary, published September 2018)
https://ok-lab.hatenablog.com/entry/20180915/1536986152
One spiral chip request led Mr. Okada to accept rounder tips
In an entry published in October 2018, a customer requested a ball-like tip, hoping it would reduce injury. Mr. Okada initially said his own experience had not suggested this was necessary. He then reported experiencing bleeding and agreed to the requested change. The diary does not record how the customer's finished chip felt in use.
(Source: ok-lab's diary, published October 2018)
https://ok-lab.hatenablog.com/entry/20181013/1539409481
A shallower rectal chip loop addressed bleeding and catching concerns
In an entry published in November 2018, Mr. Okada considered a proposed loop about 5cm wide and 5cm deep a bleeding risk for himself. He reduced its downward depth to about 3cm, retaining the width, and reported a successful personal trial. He also believed this addressed the customer's concern about an exposed end catching the bowel wall.
The rounded-loop tip (a rounded returning end) had planned specifications of about 11cm length, 3cm, 4cm, or 5cm width, and 3cm downward depth. The 4cm width cost ¥7,000 (about $45 at ¥156 = $1, rate as of 2026-09-04) excluding tax; custom pricing increased by ¥350 (about $2 at ¥156 = $1, rate as of 2026-09-04) per additional 1cm of resin-strip length. Mr. Okada offered other specifications by custom request.
(Source: ok-lab's diary, published November 2018)
https://ok-lab.hatenablog.com/entry/20181123/1542963370
If you see blood in your urine, even a small amount or for the first time, do not wait and see. See a urologist right away. If you suddenly cannot urinate, or the device cannot be removed, do not try to fix it yourself. Go to a medical facility, including emergency care, immediately.
How rectal prostate massager shapes changed over time
| Published | What the diary said then |
|---|---|
| Aug 2018 | Rectal designs appeared alongside custom length and curve choices. |
| Sep 2018 | Intended bowel locations led to plans for separate shapes. |
| Oct 2018 | Bleeding changed Mr. Okada's response to a rounded-tip request. |
| Oct 2018 | U-turn and spiral models received distinct specifications and prices. |
| Nov 2018 | A shallower returning loop addressed bleeding and catching concerns. |
| Feb 2019 | A smaller spiral was introduced specifically as a bowel aid. |
| Nov 2019 | Glass trials exposed problems keeping longer designs in place. |
| Dec 2019 | Ceramic shapes arrived with separate prices for custom work. |
| Sep 2022 | Silicone covering replaced exposed aluminium after scratching problems. |
| Jul 2025 | Flexible balloon-shaped loops introduced a different construction. |
OK Prostate Chip products related to rectal prostate massager shapes
The current list includes these named shapes; historical dimensions do not establish today's size options.
Products that appear in these entries
| Product (official name) | Price incl. tax | Relation to this topic |
|---|---|---|
| Single-bump resin U-turn (OKプロステートお尻チップ 樹脂素材1コブUターン型) | ¥5,500 (about $35 at ¥156 = $1, rate as of 2026-09-04) | October 2018 presented the shorter U-turn as a beginner model. |
| Two-bump resin U-turn (OKプロステートお尻チップ 樹脂素材2コブUターン型) | ¥6,600 (about $42 at ¥156 = $1, rate as of 2026-09-04) | October 2018 described the longer U-turn's different intended contact area. |
| Resin spiral (OKプロステートお尻チップ 樹脂素材螺旋型) | ¥8,800 (about $56 at ¥156 = $1, rate as of 2026-09-04) | October 2018 described its continuous curve and risk of being pushed out. |
| Resin rounded-loop shape (OKプロステートお尻チップ 樹脂素材尸の字型) | ¥7,700 (about $49 at ¥156 = $1, rate as of 2026-09-04) | November 2018 introduced the returning-tip shape after concerns about bleeding and catching. |
| Rectal chip support (お尻チップ用骨盤底筋サポーター) | ¥2,200 (about $14 at ¥156 = $1, rate as of 2026-09-04) | In September 2018, Mr. Okada said he planned to sell this support for rectal chips. |
| Two-bump ceramic U-turn (OKプロステートお尻チップ 陶器素材2コブUターン型) | ¥6,600 (about $42 at ¥156 = $1, rate as of 2026-09-04) | December 2019 recorded Mr. Okada's preference for this shape during shorter use. |
| Single-bump ceramic U-turn (OKプロステートお尻チップ 陶器素材1コブUターン型) | ¥5,500 (about $35 at ¥156 = $1, rate as of 2026-09-04) | December 2019 included this shape among the initial ceramic designs. |
(Source: ok-lab's diary, published September 2018)
https://ok-lab.hatenablog.com/entry/20180915/1536986152
(Source: ok-lab's diary, published October 2018)
https://ok-lab.hatenablog.com/entry/20181031/1540960147
(Source: ok-lab's diary, published November 2018)
https://ok-lab.hatenablog.com/entry/20181123/1542963370
(Source: ok-lab's diary, published December 2019)
https://ok-lab.hatenablog.com/entry/2019/12/07/162608
Products the diary mentioned as alternatives
| Product (official name) | Price incl. tax | Relation to this topic |
|---|---|---|
| Rectal chip control belt (お尻チップ用コントロールベルト) | ¥550 (about $4 at ¥156 = $1, rate as of 2026-09-04) | September 2022 mentioned this suspension option, although Mr. Okada preferred silicone tube belts for cleanliness. |
(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847
For the early custom twisted builds, glass prototypes, and specifically named ceramic free-design versions: No matching product can be confirmed on the current list.
For the silicone-covered aluminium design and the large flexible loop designs: No matching product can be confirmed on the current list.
Common worries about rectal prostate massager shapes
The reader messages concern support, hook shape, and the appearance of exposed tips.
"Can supports keep rectal chips in place?"
An entry published in September 2018 described a customer who wanted to buy a support after trying it. Mr. Okada had declined because making it required physical effort he could not manage, and training staff was difficult. He then said he intended to train staff and formally sell it for supporting rectal chips. The diary does not record whether that customer's purchase was completed.
(Source: ok-lab's diary, published September 2018)
https://ok-lab.hatenablog.com/entry/20180915/1536986152
"Which spiral chip hook shape will stay in place?"
In an entry published in October 2018, a customer asked Mr. Okada to choose a hook bend that would help retention. The request specified 30mm spiral diameter, 105mm overall length, a 60–65mm spiral section, and an additional 20mm hook. The supplied reply addresses the tip rather than giving a confirmed hook angle. The diary does not record a retention result for that requested hook.
(Source: ok-lab's diary, published October 2018)
https://ok-lab.hatenablog.com/entry/20181013/1539409481
"Does a pointed rectal chip shape raise safety concerns?"
In an entry published in November 2018, an illustrator's message raised concern about the chips' pointed appearance. Mr. Okada acknowledged that such shapes could make people uneasy. He argued that the exposed ends still served his intended bowel-aid purpose. For reassurance about appearance, he favored a closed-end design.
(Source: ok-lab's diary, published November 2018)
https://ok-lab.hatenablog.com/entry/20181123/1542963370
Buying from outside Japan
OK Lab ships internationally to countries covered by Japan Post's EMS courier service. Overseas orders are paid in advance by PayPal. Each order carries a ¥400 (about $3 at ¥156 = $1, rate as of 2026-09-04) handling fee, and EMS shipping is charged on top. These terms come from OK Lab's official sales-terms page (written here as plain text, not a link: ok-lab.net/docs/law), checked on September 7, 2026; confirm them on the official store before you order, because they can change.
Summary of this article
| What you wanted to know | The answer |
|---|---|
| What is the short answer? | Shapes changed after reported problems with fit, bleeding, and materials. |
| What is the base product? | A Japanese device placed in the urethra; this article concerns the separate rectal designs. |
| What do the shape names mean? | U-turns return toward the base; spirals coil; rounded-loop tips round off the returning end. |
| What happened in practice? | Mr. Okada's trials produced different designs, dimensions, and historical prices. |
| How did the maker respond? | He revised curves, accepted rounder tips, and reduced one loop's downward depth. |
| What changed over time? | The entries progress from early curved shapes to ceramic, covered aluminium, and flexible loops. |
| Which products are listed now? | The table identifies current resin and ceramic shapes, plus supporting accessories. |
| What did readers ask? | Their messages raised support, hook-retention, and pointed-tip concerns; some outcomes remain unrecorded. |
| How does overseas buying work? | EMS delivery, advance PayPal payment, a ¥400 (about $3 at ¥156 = $1, rate as of 2026-09-04) handling fee, and additional shipping charges. |
Source: ok-lab's diary (Okada Comfortable Life Laboratory). The original entries are in Japanese; quotations on this page are translated. Photos and videos are on the original entries.
This article is a summary of the maker's development diary. The product is not a medical device and no result is guaranteed. If anything feels wrong or worries you, see a doctor. Prices, specifications and cautions change, so confirm the latest information on the official blog and the official site. Questions about ordering and shipping go to the seller.