This is a Weaver 1 Piece Base, model 48333.
These versatile bases from Weaver(R) help give your gun a versatile edge. Multi Slot Bases are constructed of tough" lightweight Aluminum so they can withstand the most powerful recoil. They accept all Weaver Top Mount Rings and accommodate the mounting of devices such as scopes" red dots and laser optics" while allowing for optimal eye relief.
Features:
Aluminum construction
Lightweight
Accommodates many mounting devices
