The Rob Roberts Final Strut Invector Plus 20 Gauge choke is designed to enhance your shooting experience with precision and reliability. Crafted from durable 174 PH U.S. Stainless Steel this choke is the result of extensive product development and advanced technology. Its specific constriction diameter of .570 ensures optimal performance particularly when used with bismuth shot shells. As a part of the RRaptor Series this choke tube offers a strong and innovative addition to your firearm. Please note that the design accommodates installation in only one barrel of an overshotgun maximizing its effectiveness and consistency.