A flush-mounted bench stop is a useful bench tool to hold stock for hand operations (particularly planing).
The serrated-tooth jaw holds stock firmly and can be adjusted from flush to 1/2" proud by a spring-loaded wing bolt.
The cast aluminum stop is non-rusting so it will not mark your work, and is soft enough that it will not chip chisel edges.
At 1 1/2" wide by 2 1/2" long, it mortises into any bench with a top thicker than 7/8" and is secured by two wood screws.
An excellent bench attachment at an excellent price.