alveytech rear sprocket, freewheel, chain plate guides for the razor mx500, mx650, rsf350, rsf650, sx500 dirt rocket alveytech this is a set of two chain plate guides complete with rear chain sprocket and freewheel mechanism for versions 22 of the razor mx500, versions 15 of the razor mx650, and version 1 of the sx500. this is also the chain plate guide that razor uses on their rsf350 and rsf650 electric sport bikes.<br/><br/> previously sold as just a set of plastic chain plate guides, this part has now been replaced by the complete assembly which includes the sprocket and freewheel. although this entire assembly is only stated to fit specific versions of the mx500 and mx650, the plastic chain plate guide and sprocket (which are the parts that break most often) will fit all versions of the mx500 and mx650 dirt rocket dirt bikes and will also fit all versions of the mx350 and mx400. so if you have an earlier version of the mx500/mx650 or mx350/mx400 and only need the plastic chain plate guides and/or the sprocket, this part will work for you if you remove the freewheel and re-use your old freewheel mechanism.<br/><br/>depending on current stock, you may receive a sprocket that is silver or black in color.