The Mazda RE twin-v-belt alternator pulley suits early 12A and 13B rotaries through to series 5 RX-7 (vehicles with 15 mm alternator shaft). Two alternator belts of the same size as the original are required. Note - does not under-drive the alternator. Key benefits: • Eliminates belt slip on the water pump/cooling fan pulley • Shares the load between two belts • Back-up belt if one belt fails Colours available: red and silver.