Troy Barbell"s amazing Competition Bumper Plates are made to the specs that the Olympic weightlifting federation requires for competitions, Our plates are considered competition training plates; the only thing they lack are a calibration for weight distribution and a certification, High grade rubber that can withstand 30,000 drops, Plates have a dead blow when dropped with little bounce, 450 mm center steel hub to create a thinner and more durable core, 50, 2 mm center hole for snug fit on the bar, 2 year warranty against defects, SKU: RTL27CR092