21405493 Serpentine Drive Belt for Penta D4 D6 Marine Engines This serpentine drive belt is designed for use with Penta D4 and D6 marine engines.It fits as a direct replacement for the part number 21405497.The belt is constructed to withstand the operational demands of marine environments and provides performance for engine accessory drive systems.It is engineered to maintain proper tension and alignment across pulleys, supporting consistent power transmission to components such as the alternator, water pump, and air conditioning compressor.This part is intended for use in marine propulsion and auxiliary power systems where durability and precise fit are required. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.