As I mentioned Electromaax has lots of kits already pre-made for lots of marine engines including Yanmar, Universal, Westerbeke, Nani, Beta, Volvo, Perkins and more..
This happens to be a Westerbeke kit with a 160A alternator. Notice that all three pulleys are anodized black. The kits come complete with the pulley's alternator, bolts, two belts, regulator, Loctite and Tef-Gel.
The silver colored pulley is not an Electromaax product it is an added pulley for the Sea Frost engine driven refrigeration system on this boat.