The Lock On O-Ring Harness is 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. Plus. this lovely harness includes a pocket that holds an optional vibrating 1-speed bullet. adding extra sensation for the harness wearer. Vibrating bullet included. Requires 1 AAA battery (not included).