This is a solid billet pulley that is much stronger than the OEM Volvo Penta raw water pump pulley that is cast aluminum.  The OEM pulley will often break upon removal.  

Direct press fit for a Volvo Penta 3857794 raw water pump.  Pulley measures 4.5" in diameter and accepts a single v belt. 

On Apr-04-16 at 11:08:20 PDT, seller added the following information: