What are retrieval thread loops for? | Different ends have different limits [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 "retrieval thread loops and birdcage ends" 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

• Retrieval thread loops developed from simple ends into extensions, birdcage shapes, and loops connected directly to the device.
• Mr. Okada proposed different fittings, but later acknowledged concerns about short threads becoming difficult to reach.
• The current product list includes loop extensions and safety parts; custom loop designs have separate historical quotes.

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.

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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: retrieval thread loops

The OK Prostate Chip is a small device placed in the urethra (the urine passage) to act on the prostate. Its retrieval thread (the attached nylon line) can have an end loop for access or hanging storage. A birdcage loop (a three-dimensional nylon end) was intended to stay open, according to Mr. Okada. Different diary designs placed these thread ends outside the body or inside the urethra.

A customer's end loop request became an option in August 2019

In an entry published in August 2019, a customer requested a loop beyond the thread's end fitting for hanging storage and easier access. Mr. Okada initially considered suggesting an existing part, then made the requested design and found it useful. He announced that loop-ended requests would be accepted.

The published maximum thread length was 27cm, plus a stretched loop of about 3cm. Mr. Okada asks customers to specify thread length separately from the loop.

(Source: ok-lab's diary, published August 2019)
https://ok-lab.hatenablog.com/entry/2019/08/17/132641

Fixed thread loops followed an adjustable version in December 2020

In an entry published in December 2020, Mr. Okada described tests of loops intended to sit inside the urethra. The earlier version used a six-hole safety part (a thread-end fitting) that allowed changes in loop length. He then tested a directly connected loop.

He preferred the simpler appearance of the direct connection, while recognizing the adjustable version's advantage. Mr. Okada suggests that a fixed loop could suit a design needing no length adjustment.

(Source: ok-lab's diary, published December 2020)
https://ok-lab.hatenablog.com/entry/2020/12/12/124126

A separate loop extension addressed uncertainty about fully internal designs

In an entry published in January 2021, Mr. Okada introduced a loop extension (separate thread with a loop at each end). He presented it for customers uncertain about designs with no thread outside the body. The published specification was 20cm of nylon thread plus loops about 2cm in diameter.

The price was ¥500 (about $3 at ¥156 = $1, rate as of 2026-09-04) excluding tax, and a 30cm version was planned. Mr. Okada strongly recommended the extension while customers remained uncertain about his fully internal design.

(Source: ok-lab's diary, published January 2021)
https://ok-lab.hatenablog.com/entry/2021/01/16/124800

Stronger thread loops were requested after bleeding with a large custom assembly

In an entry published in March 2021, a customer reported bleeding during removal after two days with a large custom assembly. The customer wanted revised ring surfaces and four-thread loops for proposed replacement designs. Mr. Okada agreed to additional surface covering and discussed changes needed to accommodate the requested dimensions.

The diary does not record the completed redesign or how it felt in use. Mr. Okada says further details would need discussion before the actual order.

(Source: ok-lab's diary, published March 2021)
https://ok-lab.hatenablog.com/entry/2021/03/13/130202

Birdcage ends addressed flat thread loops lying against the urethra

In an entry published in August 2021, Mr. Okada described replacing a conventional end loop with a three-dimensional birdcage shape. He wrote that an ordinary loop could lie against the urethral wall and become difficult to catch. He believed the birdcage shape stayed more open.

The published processing price was ¥2,000 (about $13 at ¥156 = $1, rate as of 2026-09-04) excluding tax. In another August 2021 entry, he reported little shape change after about five days of personal testing. Mr. Okada specifies that the birdcage option requires two threads.

(Source: ok-lab's diary, published August 2021)
https://ok-lab.hatenablog.com/entry/2021/08/07/125807

(Source: ok-lab's diary, published August 2021)
https://ok-lab.hatenablog.com/entry/2021/08/14/125815

A blue safety part's thread loop could tighten unexpectedly

In an entry published in March 2023, Mr. Okada explained a limitation of the blue safety part's loop. Tension on the thread below the fitting could make the loop smaller. He wrote that tension from the loop side did not make it expand.

He later found this feature useful in a separate connection design. Mr. Okada cautions that the original loop size is not easily restored.

(Source: ok-lab's diary, published March 2023)
https://ok-lab.hatenablog.com/entry/2023/03/04/123042

Short internal thread loops still concerned Mr. Okada in March 2025

In an entry published in March 2025, Mr. Okada discussed a request for short thread and a terminal loop concealed inside the urethra. He wrote that hidden thread could fold and move deeper, making access difficult. He also worried about delays when removal became urgent.

He proposed a separate wire-based end design in that entry. For customers wanting temporary thread on that design, he offered it while cautioning that the attachment was easily removable.

(Source: ok-lab's diary, published March 2025)
https://ok-lab.hatenablog.com/entry/2025/03/29/122912

An integrated nylon loop changed the whole thread structure in October 2025

In an entry published in October 2025, a customer requested an integrated nylon loop (thread returning directly to the device). Mr. Okada made it and reported that the loop resisted folding better than loose thread. He also found that paired loops separated, so the finished design included small joining points.

Published additional prices were ¥1,000 (about $6 at ¥156 = $1, rate as of 2026-09-04) up to 10cm, ¥1,500 (about $10 at ¥156 = $1, rate as of 2026-09-04) up to 20cm, and ¥3,000 (about $19 at ¥156 = $1, rate as of 2026-09-04) up to 30cm, all excluding tax. He noted that longer loops could still change shape. Mr. Okada recommends an integrated stopper when one is wanted, because auxiliary chips are difficult to accommodate on this loop structure.

(Source: ok-lab's diary, published October 2025)
https://ok-lab.hatenablog.com/entry/2025/10/25/122907

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The maker's answer to retrieval thread loops

Mr. Okada's responses depended on the construction: extra strands, loop-forming fittings, and birdcage ends presented different problems.

Separate loop extensions were proposed for a customer's strength concerns

In an entry published in February 2021, a customer requested a doubled loop extension with joining points to prevent tangling. Mr. Okada made a prototype but found the strands were not exactly equal in length. He expected their shapes to diverge further with use.

He kept terminal-loop work free at that time, including doubled terminal loops, while warning about uneven appearance. Doubling the separate extension cost an additional ¥500 (about $3 at ¥156 = $1, rate as of 2026-09-04) excluding tax because of the extra work. For strength, Mr. Okada suggests separate loop extensions might be more effective than one joined double-strand extension.

(Source: ok-lab's diary, published February 2021)
https://ok-lab.hatenablog.com/entry/2021/02/27/130152

Two-thread safety parts could not replace a screw-containing birdcage loop

In an entry published in December 2021, a customer proposed a birdcage arrangement using two-thread safety parts around a screw-shaped supplementary chip. The diary says that construction required four strands, making the proposed fittings unsuitable. The customer accepted the conventional birdcage construction instead.

The diary recorded a ¥1,100 (about $7 at ¥156 = $1, rate as of 2026-09-04) reduction from the original order. Mr. Okada's response favors the established screw-containing birdcage construction for that particular request.

(Source: ok-lab's diary, published December 2021)
https://ok-lab.hatenablog.com/entry/2021/12/04/124140

A screw with an integrated stopper replaced one requested birdcage loop

In an entry published in October 2025, a customer requested a birdcage end on a short ceramic chip assembly. OK Lab replied that the maker had nearly forgotten the birdcage construction method. The reply proposed a screw with an integrated stopper instead, at the screw price plus ¥2,200 (about $14 at ¥156 = $1, rate as of 2026-09-04).

The customer accepted, changed the requested thread length to 8cm up to the screw tip, and requested a larger stopper loop. The entry shows the build but records no customer report about its use. OK Lab proposes that screw-and-stopper end as the alternative for this request.

(Source: ok-lab's diary, published October 2025)
https://ok-lab.hatenablog.com/entry/2025/10/11/123003

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.

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How retrieval thread loops changed over time

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OK Prostate Chip products related to retrieval thread loops

Current listings cover individual parts and base chips; the custom loop builds have their own dated specifications.

Products that appear in these entries

The two-thread safety part with connection included is listed in OK Lab's own online store.

(Source: ok-lab's diary, published December 2021)
https://ok-lab.hatenablog.com/entry/2021/12/04/124140

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/01/122944

Products the diary mentioned as alternatives

The nylon loop extension is listed in OK Lab's own online store.

(Source: ok-lab's diary, published February 2021)
https://ok-lab.hatenablog.com/entry/2021/02/27/130152

Custom birdcage assemblies, doubled extensions, wire-based ends, integrated-loop builds, and the near-weightless prototype: No matching product can be confirmed on the current list.

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Common worries about retrieval thread loops

Customers asked about hanging storage, enclosing a chip, and reproducing a previously shown prototype.

"Can an end loop help with hanging storage?"

In an entry published in February 2020, a returning customer requested the same neatly gathered loop as an earlier order. The customer reported that hanging storage kept the thread straighter and avoided contact with other surfaces. Mr. Okada acknowledged the customer's earlier suggestion.

Mr. Okada showed the new order's result. He suggests that hanging storage may suit customers already using similar storage for necklaces.

(Source: ok-lab's diary, published February 2020)
https://ok-lab.hatenablog.com/entry/2020/02/01/151232

"Can birdcage loops contain a small supplementary chip?"

In an entry published in August 2021, a customer asked whether a chip could sit inside the birdcage. Mr. Okada made a prototype containing an auxiliary screw chip (a supplementary screw-shaped chip). He said only the blue version of that part could fit inside the construction he described.

Published prices excluding tax were ¥3,000 (about $19 at ¥156 = $1, rate as of 2026-09-04) for the screw, ¥2,000 (about $13 at ¥156 = $1, rate as of 2026-09-04) for the cage, and ¥1,000 (about $6 at ¥156 = $1, rate as of 2026-09-04) for enclosing the screw. He reported a production limit of less than one per day. Mr. Okada specifies two threads for this construction.

(Source: ok-lab's diary, published August 2021)
https://ok-lab.hatenablog.com/entry/2021/08/28/125823

"Could birdcage loops replace the old near-weightless prototype?"

In an entry published in October 2022, a customer requested the near-weightless prototype shown in an earlier diary entry. The customer also offered a birdcage end as a fallback. OK Lab replied that the old design had only been a prototype and was difficult to reproduce after the intervening time.

The customer accepted the birdcage option; no experience using the finished order is recorded. The diary's proposed alternative for that request was the birdcage end.

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/01/122944

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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.