This is the 4-40 x 1 in. Socket Head Bolt Sets with Lock Nuts from Du-Bro.
High strength steel construction. High round cap head screws/bolts with a hexagon socket drive insert. Plain silver flat washers (1/8 in. ID). Plain silver 4-40 lock nuts with black nylon inserts.
Thread Size : 4-40
Screw/Bolt Length : 1 in.