Leupold LRW cross-slot rings are built from strike forged steel, made in America to deliver unmatched durability and strength. Leupold CNC machining ensures perfect alignment to weaver-style bases and the anti-slip grooves eliminate the need of lapping. LRW ring screws with Nylok won't back out under recoil or vibration. This model has 30mm medium rings with a black matte finish.