Erie Tools Heavy-Duty Thread-On 5,000 PSI External Bypass Regulator/Unloader For Pressure Washers Thread-on universal trap-type external bypass regulator for pressure washers. Max Pressure: 5,000 PSI / Max Flow: 13.2 GPM Inlet: Two (2) 3/8" Male Connections. Outlet: Two (2) 3/8" Female Connections. Bypass: 3/8" Female