Has Hand toggle have unloader and discharges pump air through felt muffler. For pumps without head unloaders and tanks with check valves. 3/8" MPT x 1/8" FPT for throttle control 1/8" FPT for check valve port. Factory preset, yet can be adjusted for higher or lower pressures.
BG-Valve 131B Pilot Unloader Valve Factory setting 125PSI-150PSI – Replacement