This is a shoulder harness system for serpa holsters from Blackhawk. You can mount compatible holsters and accessories to the harness. The harness has two mounting points. One side is for the mounting of serpa holsters. The other side has two removable picatinny rail sections for compatible accessories such as magazine holsters. You can adjust the harness for height. Also, there are two loops for connecting to the wearers belt. The harness is not ambidextrous!