CNC machined, threaded brass bushings provide added strength and security for screwing down sling studs, recoil pads, and triggerguards in wood, composite, and fiberglass stocks. Lets you turn a screw in tight without the worry of stripping it out of the stock material. Heavily knurled on the outside to hold plenty of epoxy bedding for a rock-solid grip between the insert and stock. Mfg: Brownells SPECS: Brass, knurled. A 1/2" (12.7mm) long x 5/16" (7.9mm) diameter. All inserts have 10-32 tpi internal threads. Sling Stud Inserts - (2) inserts, (2) steel, dome-top sling studs, matte blued.