Olympic Rubber Bumper plates?have the same diameter regardless of their weight. This is especially important in weight lifting. It means that there is not and increased amount of pressure on certain weights, the pressure is distributed across all the weights as they are the same diameter.Each weight is different in colour, which is flaked into the black rubber, making it easier to see the difference in weight.Quality:These plates have been dropped tested 20000 times, and will last longer then the normal bumper plates.Some things to note:?5kg Bumper Plates are not intended to be used on their own. If you need to put 10kg on each side, don't put 2x 5kg on each side, rather just put a single 10kg Bumper plate on each side of the bar.