Bondage Kitty Collar with O RingCollar Width 25mm Diameter 100-140mmAdjustable Buckle Metal O-Ring Please note: We have two grades of Faux Leather and they are –Beginners/Soft Bondage: This Faux Leather is light weight and designed for soft bondage play. It feels light to wear but is not suitable for hardcore/heavy bondage. The average thickness of the PVC Material is 2mm.Hardcore/Heavy Bondage: This Faux Leather is thicker and stronger and designed for more experienced or hardcore bondage users. It is heavier to wear and more robust. The average thickness of the PVC Material is 2.5mm.Choose the grade that is most appropriate to your use.