This is a Weaver Adapter, model 48459.
increase your scope mounting options with the Weaver T-22 Base Pair. This base pair quickly and easily converts your 3/8-inch grooved receiver to accept Weaver style rings allowing for a variety of scope mount configurations. Windage adjustable and backed by 80-years of Weaver excellence" the new T-22 Base Pair is a great option for increasing the versatility of your rifle.
Features:
Lightweight aircraft-grade aluminum for rugged performance;Slotted bases accept Weaver-style scope rings;Windage adjustable
