The 120-amp Cruiser-Series Marine Alternator is a popular choice for applications with 400 to 500 amp hours of house battery capacity. Its available with a 6-groove serpentine or dual 1/2 V-belts pulley and provides sufficient horsepower load capacity. This alternator delivers a terrific combination of low-rpm and cruise-rpm output. The 120A Cruiser can be controlled by its built-in 14.1-volt single-stage voltage regulator, or with external voltage regulators like Mastervolts Alpha Pro or Balmars Max Charge models. Our intelligent, multi-stage E-MAAX charge controller is designed for use with our Cruiser Series alternators and delivers unsurpassed charging safety and performance. For use on engines with a 3.15 saddle-style mount.