Is the double-twist chip too big? | Slim and wide versions differ [OK Prostate Chip]

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 "double-twist chip sizes (Rabuka)" 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.

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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

• The maker says the wide double-twist chip may not fit people with a narrower urethra.
• Mr. Okada favors curves and opposes longer chips for beginners struggling to reach the prostate.
• The current list includes the ceramic double-twist chip at ¥6,600 (about $42 at ¥156 = $1, rate as of 2026-09-04) including tax, without specifying size options.

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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.

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Before you read: key terms

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What happens: double-twist chip sizes

The OK Prostate Chip is a small device placed in the urethra (the urine passage) to act on the prostate. The double-twist version has raised sections and more twist than the earlier designs discussed in July 2020. Its slim and wide forms differ in width and thickness, with curves that Mr. Okada describes as a safety consideration. The diary connects these shapes with fit and prostate stimulation.

The double-twist chip design reduced bulges while increasing the twist

In an entry published in July 2020, Mr. Okada explained why a shorter design request required changes. The earlier 4-point twist shape had 5 bulges: one at each end and three in its prostate section. He said fitting them into 50 mm would be difficult unless the widest part measured approximately 9 mm or less.

His proposed double-twist design instead used 3 bulges, following an existing three-bulge chip. Standard twist and cobra-style designs turned 90 degrees at a single point, while the new design turned 180 degrees.

(Source: ok-lab's diary, published July 2020)
https://ok-lab.hatenablog.com/entry/2020/07/18/124343

The double-twist chip initially carried a proposed price before tax

In an entry published in July 2020, Mr. Okada announced plans to make the double-twist chip a regular product. Its proposed price was ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) excluding tax. He matched that proposal to the existing larger cobra-style twist model's price.

Mr. Okada also reported that the ceramic maker was trying to prepare the new designs for the following week's diary. At this point, he described regular sales and the price as plans.

(Source: ok-lab's diary, published July 2020)
https://ok-lab.hatenablog.com/entry/2020/07/18/124343

Slim double-twist chip dimensions addressed concerns about width and thickness

In an entry published in July 2020, Mr. Okada worried that the design under production would be too wide and thick for ordinary customers. A wider comparison shape measured approximately 11 mm across at its widest point. The slim design targeted approximately 9 mm maximum width and slightly less thickness.

The proposed names distinguished the wide and slim double-twist versions, both described as slightly longer than 50 mm. Mr. Okada also said the slimmer shape allowed more freedom in its design. He thought the reduced width and thickness could make that version usable by more customers.

(Source: ok-lab's diary, published July 2020)
https://ok-lab.hatenablog.com/entry/2020/07/25/131210

The slim double-twist chip launch included the maker's personal impressions

In an entry published in August 2020, Mr. Okada reported that the slim version had finished firing. He described more allowance toward its tip and less curvature. He claimed that this shape could pass into the bladder more readily.

He also described pleasure from crossing the internal urethral sphincter (the closing muscle between the bladder and prostate). He had requested preparations for sales through the company's own online store beginning August 17, 2020. Mr. Okada characterized the slim version as appropriately sized for everyday use.

(Source: ok-lab's diary, published August 2020)
https://ok-lab.hatenablog.com/entry/2020/08/15/125150

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The maker's answer to double-twist chip sizes

Mr. Okada's responses emphasize fit limits, deliberate curves, and reservations about longer designs.

The custom twin double-twist chip came with an explicit refund restriction

In an entry published in August 2020, a customer who claimed to accommodate every chip offered by OK Lab asked about the double-twist model. Mr. Okada thought its approximately 50 mm length might leave that customer dissatisfied and suggested a custom twin version. After making it, he worried that its pronounced curve could prevent it from fitting.

He anticipated a possible first report of a chip this customer could not accommodate; he did not report that failure as an event. The diary does not record whether the completed piece fitted this customer. Mr. Okada stated that he would not accept a return if it did not fit.

(Source: ok-lab's diary, published August 2020)
https://ok-lab.hatenablog.com/entry/2020/08/08/130037

The slim double-twist chip follows the maker's rule about curves

In an entry published in November 2022, Mr. Okada explained the policy behind his longer designs. He said his original approach had been to avoid selling chips measuring 40 mm or more. He later introduced products in the 50 mm class to pursue stimulation beyond the internal urethral sphincter.

For that development, he established a rule that chips measuring 40 mm or more must have a curve. He described long, thin, minimally curved chips as particularly dangerous in his own judgment. Mr. Okada maintained that longer chips needed a substantial curve as a precaution.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

Double-twist chip alternatives would require the maker's assessment of prototypes

In an entry published in November 2022, Mr. Okada explained his reluctance toward a proposed long, thin, less-curved design. He recalled early custom glass chips and said straight designs measuring 4 cm or more had proved unsuitable in his experience. He emphasized that his judgment came from personal experience and customer reports, while acknowledging that future experiences might differ.

He had passed the proposal to the resin-chip maker and remained willing to consider a prototype from that maker. The diary does not record a resulting prototype or a decision after testing. Mr. Okada's stated approach was to assess any submitted prototype before deciding whether to accept the design.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

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How double-twist chip sizes changed over time

The diary does not say what the current state is.

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OK Prostate Chip products related to double-twist chip sizes

The current list includes the ceramic double-twist chip and a raised-bump option, without specifying available sizes.

Products that appear in these entries

The ceramic double-twist chip is listed in OK Lab's own online store.

The raised-bump option is listed separately in OK Lab's own online store.

(Source: ok-lab's diary, published December 2025)
https://ok-lab.hatenablog.com/entry/2025/12/13/122917

Products the diary mentioned as alternatives

In the November 2022 reply, Mr. Okada described an extended ceramic shape that added approximately 15 mm. The short version was approximately 45 mm long. He considered this among existing curved or flexible designs close to the reader's proposal, while retaining his reservations about longer beginner chips.

The extended short ceramic chip is listed in OK Lab's own online store.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

Custom twin double-twist chip, discussed in August 2020:

No matching product can be confirmed on the current list.

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Common worries about double-twist chip sizes

The recorded questions concern beginner suitability, differences in fit and sensation, and visual size comparisons.

"Is the slim double-twist chip suitable for beginners needing more length?"

In an entry published in November 2022, a reader proposed a longer, slimmer design after hearing that beginners could not reach the prostate. Mr. Okada identified the slim double-twist chip as an existing slender, long, single-piece option. He emphasized that its curve was deliberate and reflected his safety concerns.

The reply also considered curved or flexible existing products, including a resin chip with a flat auxiliary piece. The diary does not record how the beginners mentioned by the reader later fared. Mr. Okada did not recommend 40 mm or longer chips for beginners who had not yet managed to reach the prostate.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

"Do slim and wide double-twist chips feel different?"

In an entry published in March 2024, a customer asked how the slim and wide versions differed beyond their published measurements. The customer was interested in the wider version but had heard it could be too large. Mr. Okada replied that some people with a narrower urethra might be unable to accommodate it.

For people who could accommodate both, he described the wider version as giving a relaxed feeling of fullness in the prostate. He characterized the slim version as providing a sharper, more pointed stimulus. The diary does not record which version the customer selected or how it felt in use.

(Source: ok-lab's diary, published March 2024)
https://ok-lab.hatenablog.com/entry/2024/03/02/123027

"Can photographs compare slim and wide double-twist chip dimensions?"

In an entry published in December 2025, a customer ordering a slim version with bumps requested photographs to compare width and thickness. The customer also wanted to see the wide version and asked for 3 items together. Staff initially said they could not promise a photography date but might include the comparison in the weekend diary.

Mr. Okada then photographed 4 versions: wide, wide with bumps, slim, and slim with bumps. The entry also included paired views of the wide versions and the slim versions. Mr. Okada offered the photographs as a reference for customers making comparisons.

(Source: ok-lab's diary, published December 2025)
https://ok-lab.hatenablog.com/entry/2025/12/13/122917

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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.

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Summary of this article

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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.