What ceramic chip sizes are there? | Sizes depend on the shape and publication date [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 "ceramic chip sizes and 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.

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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

Ceramic chip sizes developed separately across short, semi-long, extended, long and twisted shapes.

Mr. Okada added smaller options but said some shapes could not be offered at every length.

The current list includes ceramic products and prices, but it does not confirm which sizes remain available.

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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: ceramic chip sizes

The OK Prostate Chip is a small device placed in the urethra (the urine passage) to act on the prostate. The ceramic versions come in several lengths, widths and shapes, with later entries adding twists and surface bumps. Mr. Okada also describes versions with a curved extension at the rear. These are historical measurements from release announcements, while the current product list gives product names and prices without size options.

Curved ceramic chip sizes included a rear extension without a hole

In an entry published in June 2019, Mr. Okada announced curved-tail ceramic chips alongside the ordinary ceramic range. The curved tail (a rear extension intended to help the chip stay in position) had no hole. It added about 15 mm to the corresponding ordinary ceramic chip.

The plan covered three sizes each for short, semi-long and Kakusei shapes. Mr. Okada presented the curved shape as a way to help maintain the chip's position.

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/01/155432

Smaller ceramic chip sizes arrived with distinct short and semi-long measurements

In an entry published in June 2019, the short ceramic chip's ss size was released at 28 mm long and 7 mm wide. Short S was listed at 31 mm long and 8 mm wide. The same chart gave M as 32 mm long and 9 mm wide, and L as 34 mm long and 10.5 mm wide.

The semi-long ceramic chip gained SS, with a length of 37 mm and listed widths of 7, 8, 7, 7 mm. Its other sizes remained in the chart alongside the new addition. Mr. Okada expressed a personal preference for the S or SS curved-tail versions for prolonged wear.

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/22/123034

Twisted ceramic chip sizes began with three versions at glass-model prices

In an entry published in December 2019, the first ceramic twist offerings were short S, short M and semi-long cobra-twist M. Their maximum widths were all about 8 mm. The ceramic short twist and semi-long cobra-twist were priced the same as their glass counterparts; the paragraph gives no yen amounts.

Formal sales had not yet begun, so these were early offerings through a temporary ordering arrangement. Mr. Okada told interested buyers to specify the ceramic version when ordering through the corresponding glass listing.

(Source: ok-lab's diary, published December 2019)
https://ok-lab.hatenablog.com/entry/2019/12/07/162608

Expanded twisted ceramic chip sizes used lengths that included their covers

In an entry published in December 2019, the semi-long ceramic cobra-twist gained S and L. Its approximate lengths were S: 41 mm, M: 43 mm and L: 47 mm.

The short ceramic twist gained SS, with approximate lengths of SS: 32 mm, S: 34 mm and M: 36 mm. Both sets of measurements included the resin cover (the covering counted as part of the finished chip's length).

(Source: ok-lab's diary, published December 2019)
https://ok-lab.hatenablog.com/entry/2019/12/28/131319

Long four-point ceramic chip restocking was planned after a January stock shortage

In an entry published in January 2020, the long ceramic four-point twist was out of stock following concentrated orders. Restocking was expected in about 2 weeks, with 3 sizes: S, M and L.

The extended ceramic cobra-twist was available, with its S, M and L range also expected in about 2 weeks. A later entry published in January 2020 confirmed three sizes for the ceramic Kakusei cobra-twist. These announcements record historical stock and size changes; the current list does not specify size availability.

(Source: ok-lab's diary, published January 2020)
https://ok-lab.hatenablog.com/entry/2020/01/11/151714

(Source: ok-lab's diary, published January 2020)
https://ok-lab.hatenablog.com/entry/2020/01/25/150127

Short twisted ceramic chip sizes grew again when L was added

In an entry published in April 2020, the short ceramic twist gained L alongside SS, S and M. Compared with M, L was about 1 mm longer, with each width also about 1 mm greater. Its rear-end width was about 10 mm.

(Source: ok-lab's diary, published April 2020)
https://ok-lab.hatenablog.com/entry/2020/04/11/151453

Textured ceramic chip sizes retained length and width but gained thickness

In an entry published in October 2020, Mr. Okada introduced ceramic chips with added surface bumps. He said their length and width were generally unchanged from the earlier versions, but their thickness had increased considerably.

Mr. Okada also stated that he had not tested these new chips in use. His suggestion that they would feel fuller was therefore an expectation, rather than a result from testing these versions.

(Source: ok-lab's diary, published October 2020)
https://ok-lab.hatenablog.com/entry/2020/10/17/121023

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The maker's answer to ceramic chip sizes

The maker added sizes in stages, offered a specific alternative for one unavailable shape, and limited the textured range.

Initial ceramic chip sizes launched before the smallest options were ready

In an entry published in June 2019, ceramic sales began with 8 sizes. Short had M and L; semi-long and extended shapes each had S, M and L.

Mr. Okada planned to add short S and SS, plus semi-long SS, about 2 weeks later. He asked customers seeking those smaller options to wait for the additions.

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/08/144200

Semi-long ceramic chip sizes could not accommodate the four-point twist design

In an entry published in January 2020, Mr. Okada said he could not offer a semi-long four-point twist because of its proportions. He explained that the long four-point twist's S size had deliberately been made small with semi-long users in mind. Mr. Okada suggested that S option for someone already able to accommodate a semi-long L, presenting this as his judgment about fit.

(Source: ok-lab's diary, published January 2020)
https://ok-lab.hatenablog.com/entry/2020/01/25/150127

Textured ceramic chip sizes carried an extra charge within a limited range

In an entry published in October 2020, the announced surcharge for surface bumps was ¥1,000, (about $6 at ¥156 = $1, rate as of 2026-09-04) tax excluded, compared with versions without bumps. The offer was limited to 12 ceramic designs introduced on the blog: six in that entry and six introduced earlier.

Orders for the new group were planned to begin the following week. Mr. Okada directed buyers to a temporary bump-addition product for those orders.

(Source: ok-lab's diary, published October 2020)
https://ok-lab.hatenablog.com/entry/2020/10/17/121023

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How ceramic chip sizes changed over time

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OK Prostate Chip products related to ceramic chip sizes

The current list confirms these products and prices, while the dated diary entries supply their historical size information.

Products that appear in these entries

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

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

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/08/144200

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/22/123034

(Source: ok-lab's diary, published July 2019)
https://ok-lab.hatenablog.com/entry/2019/07/06/152113

(Source: ok-lab's diary, published December 2019)
https://ok-lab.hatenablog.com/entry/2019/12/28/131319

(Source: ok-lab's diary, published January 2020)
https://ok-lab.hatenablog.com/entry/2020/01/25/150127

(Source: ok-lab's diary, published April 2020)
https://ok-lab.hatenablog.com/entry/2020/04/11/151453

Products the diary mentioned as alternatives

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

(Source: ok-lab's diary, published January 2020)
https://ok-lab.hatenablog.com/entry/2020/01/25/150127

Custom 6 mm glass chip, June 2019: No matching product can be confirmed on the current list.

Early ceramic twist versions, December 2019: No matching product can be confirmed on the current list.

Temporary bump-addition listing, October 2020: No matching product can be confirmed on the current list.

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Common worries about ceramic chip sizes

The customer request behind the smaller-size discussion concerned a custom glass chip, rather than a ceramic size specification.

"Can chip sizes go as narrow as 6 mm?"

In an entry published in June 2019, a customer who had previously requested larger custom chips asked for a glass chip 6 mm wide. Mr. Okada said this was the narrowest chip he could make; his statement concerned that glass-chip request.

He described the request as the inspiration for adding SS ceramic sizes. The diary does not record whether the custom order was completed or how it felt in use. Mr. Okada favored a stopper chip (an optional part proposed as a safety precaution) for such a small chip.

(Source: ok-lab's diary, published June 2019)
https://ok-lab.hatenablog.com/entry/2019/06/08/144200

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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.