This General Pump Unloader K7.2 4.2-6.6/3000 (8.712-619.0) is flow actuated and commonly used on Landa power washers, but can also be found on alternate brands. Designed to remove high pressure from all pressure washer lines when the trigger gun is released (bypass mode), it features all stainless and brass internal components with no external moving parts, and its simple design provides for easy maintenance and service.