Alternator 3.15" Dual Foot Saddle J10 Serpentine Pulley - 170A - 12VBalmar offers a wide range of alternator power upgrades designed specifically for marine industry applications. Balmar installs high reliability bearings, robust rectifier diodes and improved heat-sinking capabilities on all our alternators to ensure improved system reliability combined with increased charging power.Features:. 3.15" Dual Foot Saddle. J10 Serpentine Pulley. 170A. 12V. This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.