Rivet setter with concave end and knurled handle. Made in the USA by C.S. Osborne. The rivet setter sets the small double cap rivets & the small rapid rivets. The rivet setter allows you to rivet in tighter spots than setting with only a metal hammer. Best to use the CS Osborne rivet setter with a metal anvil on the underneath side of the rivet on a sturdy work table. The setter is 3 7/8 inch long with a 3/8 inch diameter.