Our QD Swivels, made from high-quality steel, are designed to withstand years of use and are compatible with most universal fitting sling mounts. Compatible with Most QD Swivel Mounts Our QD Swivels were designed to be compatible with the industry standard swivel mounts. The placement of the ball bearings specifically aligns to the most commonly used mounts, as well as most universal-fit mounts. NOTE May not fit all Ruger AR-556 QD sockets.