This is the 2-56x1/2" Mounting Bolt Sets with Blind Nuts from Du-Bro.

Features

High strength steel construction for mounting engines.
Round head screws/bolts with a slotted drive insert.
Plain Silver 2-56 blind nuts.
Plain Silver flat washers (.08" ID).
Plain Silver slotted lock washers (.08" ID).

Includes

(4) Bolts
(4) Flat Washers
(4) Lock Washers
(4) Blind Nuts

Specifications

Thread Size: 2-56
Screw/Bolt Length: 1/2"