Magpul RSA QD Rail Sling Attachment -The RSA-QD provides a forward attachment point for the Magpul MS4 Sling and other push-button QD slings. Made from corrosion resistant steel, mounts on 1913 Picatinny rail, and places the attachment point at an angle optimized for comfortable two-point sling use while maintaining easy push-button access. Made in U.S.A. Provides a forward attachment pointCorrosion resistant steelMounts on 1913 Picatinny railMade in U.S.A.