This ball gag with VAC-U-LOCK is made from stainless steel and leather. Put the ball bag in the mouth and tighten the straps on both sides tight enough by attaching the buckles. Fits all vac-u-lock dildos and/or HUNG dildos. So attach your favourite toys on this ball gag! The Circumference for your head fits starting from 45 cm up to 57 cm, the diameter of the Ball gag is 41 mm.