Original Whale tricuspid replacement valve, engineered to maintain one-way flow in marine and RV waste systems. It is the internal check valve used in all Whale Gulper pumps (e.g., Gulper 220, 320, 360), installed inside the pump head behind the diaphragm to prevent backflow when the pump stops. Additionally, this valve functions as the internal sealing mechanism in Whale inline check valves LV1218 and LV1219, sharing the same operating principle to maintain priming and prevent reverse flow in suction lines. Suitable for bilge, shower, and grey water systems.