The Rob Roberts Final Strut Optima 12 GA choke is designed for exceptional performance with bismuth shot shells. Precision-engineered from 174 PH U.S. Stainless Steel this choke embodies years of innovation and cutting-edge technology. With a constriction diameter of .660 it is a powerful addition to the RRaptor Series ensuring optimal shot patterns. Ideal for enhancing your shooting experience this choke is specifically tailored for single-barrel use maximizing the effectiveness of your 12-gauge firearm.