GrovTec heavy duty, limited rotation push button swivel bases allow the user to position a sling attachment point wherever it is needed for the preferred sling. The 9/16-18 threads screw into wood or synthetic stocks and allow a standard push button sling swivel to be attached with ease. These limit your rotation to approximately 15 degrees. Comes with one set of sling swivel bases. Specifications: Made of steel Heavy Duty Limited Rotation Black 100% Made In USA