BDSM Posture Collar with O Ring Collar Width 55-85mm Length 330mm Diameter 125-145mm Please note: We have two grades of Faux Leather and they are Beginners/Soft Bondage: This Faux Leather is lightweight 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.