MARCHESINI MJ rear sprocket for Marchesini Model 6 MJ Corse MJ.729 €59.27 High quality duraluminium (ergal) rear sprocket for Marchesini Model 6 with chain pitch 415, 415R, 520, 525 and 530 with number of teeth from 34 to 60. Select the chain pitch and number of teeth you need by clicking below. Add to cart