Front flip-up sight is made of tough, metal-reinforced polymer with steel apertures for both light weight and durability. Sights snap up into position instantly under robust spring pressure when the finger pad is depressed, and can be easily retracted to the folded position with one hand. Front sight is designed to be mounted to a handguard rail on the same plane as the receiver rail; it is not designed to be mounted on a gas block. Rear sight available separately. Sights are designed to lean to the rear and should not obtain a vertical position when installed Mfg: A.R.M.S.,Inc SPECS: Reinforced polymer, matte black. Steel apertures, matte black. Sight is 5/8" high when folded, 1 3/4" total height when deployed. #71L-F Front Sight 2 1/4" long, 13/16" wide. Not for use on a gas block.