The roller material is round steel,it’s suitable for C30R crawler carriers,beside,YANMAR have others tracked carriers like C08、C12R-C、C50R. What model undercarriage parts of YANMAR excavators we have done? YANMAR excavators have ranging from 0.8t-10t class excavators,have 2 series of models,“VIO” and“SV”,have steel tracks and rubber tracks,our factory have done many mini excavator undercarriage parts like track roller,carrier roller,sprocket,idler,track link assy,track shoe assembly etc,those parts can be used in VIO12,VIO17,VIO20,VIO25,VIO30,VIO35,VIO50,VIO55,VIO80,VIO80, SV08,SV100 excavators,more informations,pls contact us without hesitate. Our products are according to the standard of OEM to manufacture.