5/16-18 x 3″ Security Machine Screw – Round One-Way Head – Steel – Zinc – FT – UNC – USA – 100 Pk Hot Picks

Security fasteners provide an added level of security by their drive design that prevents removal with ordinary screw drivers. Maximum torque transfer & positive tool engagement means easier drive installation with less pressure & slippage. Requires matching driver bit.
Round Head screws are widely used for general purposes, featuring a high crown with a deep recess and smaller diameter head than truss or pan heads.