Originally Posted by ZeroZeta

My Japanese is a little rusty but I think "One Off" might also be the Mfr. as well as the description.

Looks like these guys do some auto prototyping.

Also found a diffuser and vented fender that might be theirs. Here is the contact info I found

One-off parts and sales | one-off club Onuma Works

One-off club | production and sale of one-off parts

Onuma Works Co., Ltd.

〒 270-2241
Matsudo, Chiba Prefecture Matsudoshinden 129-1 [Access]

TEL :047-362-7111 FAX :047-367-6559