This is a Warne Scope Mounts 1 Piece Base known as the Tactical, model M673-20MOA.
Machined from solid steel in both standard and 20 MOA configurations" Warne Tactical Rails are designed around the Mil-Spec Picatinny style rail system and provide a strong and true platform for optics mounting.
Features:
Warne Tactical Rails allow the use of Picatinny or standard Weaver style rings
Constructed of solid steel
Cross slots feature 1913 Mil-Spec design