Clutch drive (steel)plate set 450 EXC-R
ProX steel clutch plates are made to meet and exceed OE standards. These are mostly made in Japan. Manufacturers sometimes use alloy plate instead of steel to lower rotating weight. Spinning weight has more effect on the engine performance than static weight. A lighter clutch pack will allow the engine to build revs quicker. Some off road rider prefer the slower gain in engine speed that comes from steel plates, a little like a heavy flywheel. You can use steel plates in bikes that are fitted with alloy plates. Steel plates do last longer and don't contaminate the oil as much as Alloy plates. Use bike selector for exact application.
Image is generic actual will differ.