Mitchell Defense Enhanced SP4 Gas Rings 3 Pack Silver. Their advanced SP4 coating reduces friction and enhances cycling during high-round-count firing. Sold as a 3-pack these rings are a valuable upgrade for rifle maintenance improving reliability in both suppressed and unsuppressed AR-15 systems. Specifications for Mitchell Defense Enhanced SP4 Gas Rings: Manufacturer: Mitchell Defense Color: Silver Fabric/Material: Steel Gun Make: AR Platform Gun Model: AR-15 Gun Type: Rifle Features of Mitchell Defense Enhanced SP4 Gas Rings SP4 high-lubricity coating for extended ring life Reduced friction for smoother cycling Increased heat resistance for high-volume firing Compatible with standard AR-15 bolts Package Contents: Mitchell Defense Enhanced SP4 Gas Rings What firearm models does the manufacturer say Mitchell Defense Enhanced SP4 Gas Rings is compatible with? The manufacturer suggests that Mitchell Defense Enhanced SP4 Gas Rings is compatible with AR-15Mitchell Defense 661001: Enhanced SP4 Gas Rings 3 Pack Silver