Is the aluminum prostate massager bare metal? | Silicone covered it, but early seals failed [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 aluminum rectal chips 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

Mr. Okada found aluminum prone to scratching and reported sealing problems in early rectal chips.

Mr. Okada replaced the initial covering with silicone designed to fit directly against the aluminum.

No matching product can be confirmed on the current list.

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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: aluminum prostate massagers

The OK Prostate Chip is a urethral device intended to stimulate the prostate while remaining in the urine passage. The aluminum rectal chip is a separate bent strip intended to stimulate the prostate from inside the rectum (the passage beyond the anus). Mr. Okada described a flat shape with a silicone outer covering. Its suspension (hanging support) was intended to alter the chip's pressure and movement. The entries follow changes to its specifications and sealing during September and October 2022.

An aluminum prostate massager prototype still awaited Mr. Okada's own tests

In an entry published in September 2022, Mr. Okada introduced an aluminum prototype with a U-turn shape (a strip bending back toward its base). He described a two-bulge design, made to mark news of a patent allowance. Aluminum was a new material for this development.

Mr. Okada thought the material and manufacturing approach would allow freely chosen sizes without the strength problems he associated with an earlier large custom build. He planned to test the prototype himself before starting sales.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/03/122644

Aluminum prostate massager dimensions distinguished strip thickness from overall size

In an entry published in September 2022, the aluminum core measured 2 mm thick and 10 mm wide. A silicone tube with a 1 mm wall brought the covered strip to approximately 4 mm thick and 12 mm wide. The planned rectal lengths were 80 mm (M) as standard, with 70 mm (S) and 90 mm (L) options.

The chip's overall bulge was about 25 mm. Mr. Okada linked these modest dimensions to intended use alongside the urethral chip and 24 hours of wear. The diary does not record customer results for that combined use.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

The aluminum prostate massager suspension used coated fittings and flexible tubing

Another part of the entry published in September 2022 described the hanging assembly. Its fittings used 1 mm wire inside 2 mm tubing, with a stated finished size of 2 mm. The hanging cords were silicone tubing with an outside diameter of 2 mm.

The cord specification allocated 1 m of tubing as 50 cm for the front and 50 cm for the rear. Mr. Okada described support from either the waist or shoulders. He said this suspended arrangement allowed almost no rotation of the chip.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

The aluminum prostate massager price depended on its hanging-cord package

The entry published in September 2022 priced the plain aluminum rectal chip without hanging cords at ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) excluding tax. The version supplied with silicone hanging cords cost an additional ¥1,000 (about $6 at ¥156 = $1, rate as of 2026-09-04) excluding tax. Mr. Okada described the plain version as an option for buyers who could provide their own cords.

He was reluctant to accept larger custom builds because the physical effort and production time increased sharply. Such work could require help from someone with greater physical strength, he explained. His preference was to avoid those larger commissions.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

Mr. Okada claimed bowel movements were possible with the aluminum prostate massager

In the entry published in September 2022, Mr. Okada claimed bowel movements were possible with the suspended aluminum rectal chip still present. He wrote that soft stool could pass between the chip and the anal sphincter (the ring-shaped muscle surrounding the anus). He described a different result with firmer stool: the chip could come out with it.

According to his account, the spring force of the hanging tubes then flipped the chip back against the buttocks. The diary does not record a customer's outcome for this claimed function.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

Aluminum prostate massager pressure depended on suspension direction, according to Mr. Okada

The entry published in September 2022 described pressure adjustment as a feature of the hanging assembly. The flat chip had 2 suspension directions: the perineum (the area between the anus and scrotum) and the tailbone. Mr. Okada wrote that the direction and strength of this support changed pressure toward the prostate.

He regarded suspension as a way to vary pressure without relying only on a larger device. The diary does not record how customers experienced these pressure changes.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/17/123057

This spiral prototype differed from the aluminum prostate massager in purpose

In an entry published in October 2022, Mr. Okada introduced an aluminum rectal spiral (a coiled strip) as a prototype. It used a long strip of silicone-covered aluminum. He described this spiral as a bowel-movement aid, while the earlier suspended chip was presented as a prostate massager.

For that reason, hanging parts were not standard equipment for the spiral. He planned personal use tests before deciding whether to begin sales. The diary does not record the results of those spiral tests.

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

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The maker's answer to aluminum prostate massagers

Mr. Okada addressed surface damage first, then revised the sealing and the fit between silicone and aluminum.

Scratching led Mr. Okada to cover the aluminum prostate massager

In the entry published in September 2022, Mr. Okada said the first aluminum rectal chip scratched too easily. He responded by covering the entire aluminum strip with silicone, intending to address both scratching and dirt buildup. Both ends of the chip and its hanging fittings were sealed with silicone.

According to his description, every outside surface was now silicone, including the fittings and flexible hanging cords. At that stage, Mr. Okada regarded the scratching and dirt problems as resolved.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

Aluminum prostate massager end seals needed improvement after the first covering

In the entry published in September 2022, Mr. Okada acknowledged that the silicone tubing had not completely sealed the aluminum strip. He reported strengthening the seals. He otherwise regarded the shape and the way the hanging system applied force as essentially complete.

His assessment concerned the design at that point in development. The diary does not record whether an earlier buyer received this sealing revision.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/17/123057

Yellowing inside an aluminum prostate massager revealed liquid beneath its covering

In an entry published in September 2022, Mr. Okada traced yellowing in his test chip to a poorly sealed tube end. He wrote that some liquid had entered beneath the covering. The affected item was an early, imperfect example he had used for his own tests.

His response was to eliminate the space between the tube and aluminum throughout the portion intended to remain inside the body. He reported that this was technically possible, but greatly increased manufacturing work. The entry leaves him weighing that production burden.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/24/122837

A new aluminum prostate massager coating method addressed gaps at lower cost

In an entry published in October 2022, Mr. Okada reported finding a less costly way to eliminate spaces around the aluminum. He described a long strip with silicone adhering directly to the metal, equivalent to a silicone coating. The earlier construction had depended on an aluminum strip inside ready-made tubing.

Mr. Okada said future products would use the fully coated strip. He stated that this would prevent body fluids from reaching the aluminum. The diary does not record independent testing of that claim.

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

Earlier aluminum prostate massager coverings had gaps and wrinkles, Mr. Okada acknowledged

In the entry published in October 2022, Mr. Okada explained that the early silicone covering did not fit tightly against the aluminum. As a result, those versions had spaces and wrinkles. He presented the closer-fitting covering as a product improvement and apologized to people who had already bought an earlier version. The diary does not record whether those earlier purchases were replaced or modified.

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/08/122859

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How aluminum prostate massagers changed over time

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OK Prostate Chip products related to aluminum prostate massagers

The control belt is the current accessory Mr. Okada mentioned as another way to provide hanging support.

Products that appear in these entries

No current product appears in these entries.

Products the diary mentioned as alternatives

The rectal-chip control belt is listed in OK Lab's own online store.

(Source: ok-lab's diary, published September 2022)
https://ok-lab.hatenablog.com/entry/2022/09/10/122847

Aluminum rectal chips and the spiral prototype: No matching product can be confirmed on the current list.

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Common worries about aluminum prostate massagers

(The material contains no questions from readers.)

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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.