Era-Tac 57050-series Picatinny rails are engineered for an ultra-precise fit to the receiver achieving maximum accuracy potential. They attach via Torx screws are fully-machined from solid high-grade aluminum and are Type-III anodized (black) rendering them corrosion-proof. The perfect solution to providing a solid stable purchase for a good set of rings or 1-piece optic mount on your long gun.