100% Natural Rubber : All the weight sheets are made of high-density pure rubber, which has excellent elongation and recovery properties. No Bending : The weight plate with a thickened stainless steel metal ring has withstood numerous professional drop tests without bending. Odorless : Each rubber plate is treated with a Unique curing process that eliminates offensive odors. IWF Spec: We calibrate our plates beyond IWF standards and now maintain a tight tolerance of +/- 0.05%. Unique details : The weight plates have raised and deep edges, making it easier and safer to pick up and handle the weight of barbells and other weightlifting equipment.