These two-piece Xtreme Tactical Bases are precision machined from solid steel and engineered for maximum mounting flexibility on any rifle. The mil-spec cross slots ensure a secure mount of scope rings or any optics accessory that can be mounted to Weaver- or Picatinny-style rails. Front base is reversible to provide multiple ring positions to accommodate various scope lengths. Bases provide minimal height and weight.
Sinclair, Issue:4A, Page:204