External tentioned clutch, 2,1,0,-1 gear structure, belt transmission, dual clutch option, 6.5hp power, aluminum gear ... (3pc x 4units, 24pcs in total, 3+1 structure);Optional configuration:Dual clutch structure, 4pc x unit dry field blades (32pcs in ... total), 2+1+1 structure Optional front wheel (aluminum or ...