The Carlsons Bismuth BB 20ga Extended Range Choke Tube is expertly crafted to deliver superior performance with bismuth ammunition. Made from 17-4 heat-treated stainless steel using CNC precision machining this choke tube boasts a longer parallel section inside the choke for tighter more consistent patterns compared to standard factory chokes. Designed through extensive testing with various loads it ensures devastatingly dense patterns that are perfect for hunting or shooting sports. Compatible with all lead Hevi-Shot and steel shot up to size #2 this choke tube is versatile and reliable. Its Optima HP configuration and durable construction make it a standout choice for any 20-gauge shooter seeking improved accuracy and performance.