This is a 1 inch diameter tenon cutter utilizing 15mm square carbide inserts secured in place with M6 machine screws. It is driven by a drill using a ½inch square socket drive adapter. There are additional M6 holes in the body of the cutter for the insertion of M6 set screws. These allow you to limit the length of the tenon OR provide a standoff to prevent plastic and wood rubbing. This can be used on wood smaller than 2.5 inches.

It works remarkably well and I've used it to make a very study croquet mallet.