Calypso O-Ring & Stud Banned Apparel Collar - An adorable collar with tiny chrome coloured pyramid studs and a small o-ring in the centre. Add some classic punk styling to vamp up your outfit. Measuring about 1cm wide, the collar is 100% PU. The o-ring measures approximately 15mm in diameter. The collar fastens at the back with a small buckle. The smallest hole is around 31cm and goes up to around 36cm.