The rr1 choke is the premium choice for close-range targets.The internal cuts provide optimal pattern density when paired with the correct loads.These choke tubes are built from years of product development and innovations using the highest advanced technology available.They are made out of 17-4 ph u.S.Stainless steel.*over-shotguns can have a rraptor choke in only one barrel.The design of the choke does not allow for placement in both barrels*Gauge: 12 GaugeMaterial: 17-4 PH Stainless Steel