The following kit is a \"bolt for bolt\" replacement for the standard alternator on a Yanmar diesel. The kit features a Series 23 Powerline alternator with a dual foot mount and 7.1\" bolt to bolt layout. The kit includes a smart three step regulator with Bulk, Absorption, and Float modes, turn-on delay to protect belts, stepped voltage at turn on, GEL battery protection, Halogen light protection, and many other features that are intended to optimize charging of expensive batteries. The kit includes a wiring harness and  instructions. The kit includes a pulley with a 1/2\" groove if your engine is equipped with a belt other than 1/2\" wide, please call us so we can provide the proper pulley in your kit