Color-coded bumper plates. Each solid rubber plate is 17.7" in diameter with steel inserts that reinforces the hole and protects the bar. Designed for all Olympic-style platform lifts. Fits 2" Olympic size bar sleeves. Made from solid Virgin Rubber+58%SBR with 2 inch Stainless Steel inners Weights are available in :10lb,15lb,25lb,35lb,45lb,55lb and 5kg,10kg,15kg,20kg,25kg. hardness SHA (85-95) Thicknesses 5kg Grey - 28mm 10kg Green - 47mm 15kg Yellow - 61mm 20kg Blue - 70mm 25kg Red - 90mm Weight tolerance:+-1% Rubber Training Bumper Plates suitable for Olympic lifting Ideal for commercial gyms, schools or home gyms, etc