This is a brand new Dunlop Straplok Dual Design Strap Retainer system. These come in all back and feature a groove and ball design that allows the strap to rotate freely without catching. They are made from case-hardened steel, can be used with several guitars thanks to the interchangeable buttons and have been release-tested up to 800 lbs. These are highly popular straplocks and have been used by countless professionals.