There's no longer a need to search for front and rear bases for your most popular firearms. Weaver Base Pairs feature tough, lightweight aluminum construction to hold up to the most powerful recoil. The Weaver cross lock design means a tight, secure fit on your firearm. These bases accept all Weaver top mount cross lock rings. Cross-lock channel accepts all Weaver cross-lock rings Front and rear matched pairs for specific firearms Lightweight aluminum construction designed to stand up to the roughest recoil