Sling swivel stud, 3 slot picatinny rail adapter for bipods; attaches to sling swivel stud on your rifle so you can fit bipods that require a picatinny / weaver rail mount. Has a rubber base that fits firmly against the stock to prevent damage. This also provides an alternative swivel stud for sling and for attaching lasers, grips etc 75mm long 35mm wide rail 21.25mm wide, 38mm long.