The Lock On O-Ring Harness is a sexy. comfortable way to expand your strap-on options! Its nylon straps are adjustable to fit around up to 60-inch waists. The Lock On attachment holds any Lock On compatible dildo securely in place during even the most vigorous play. The harness can also be used without the Lock On attachment. to accommodate any harness compatible dildo. Plus. this lovely harness includes a pocket that holds an optional vibrating 1-speed bullet. adding extra sensation for the harness wearer. Vibrating bullet not included. Requires 1 AAA battery (not included).