3812159 Alternator D-30 Drive Belt for Penta D1 D2 Marine Engines 21951188 This alternator drive belt is designed to fit Penta D1 and D2 marine engines.Identified by part numbers 3812159 and 21951188, the D-30 belt power transmission between the engine and alternator.Constructed for marine use, it resists wear and maintains tension under typical operating conditions.The belt supports consistent alternator performance, aiding in efficient during engine.Intended as a direct replacement, it meets the specifications for fit and function in compatible marine propulsion systems. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.