The XTR Signature Rings were designed for the tactical shooter. They deliver plenty of holding power, with less weight. Unique, self-centering, dual steel clamps with full cross-through connection assure proper center on any width Picatinny rail, while adding extra strength. Revolutionary Pos-Align Inserts technology, in a tactical ring configuration Pos-Align Inserts guarantee perfect centering and maximum scope-to-ring contact for tremendous gripping power without damaging the scope finish. Burris 420221 XTR Signature Rings Matte Black 30mm.