This was a special order Takahashi item to mount the 7x50 finder to an accessory ring in place of the focuser mounting. It was designed for the Tak BRC-250 but painted by Takahashi to match their normal lite green trim.
The bracket is like new and mounts to the optional accessory rings sold for any Tak scope, 60mm, 78mm, 102mm, 128mm, etc....
Pictured on finder that is listed separately. Sell bracket for $30 + shipping.