OTC 4221 75 GPM Hydraulic Flow Tester 75 GPM hydraulic oil flow tester accurately measure oil flow temperature and pressures against manufacturers specifications Troubleshoot hydraulic circuits and isolate faulty components on mobile equipment machine tools fork lifts agricultural and industrial tractors Automatic pressure compensating load valve lets you increase flow without affecting the pressure settings Temperature flow and RPM readings are displayed in metric or English and accurate to within plus or minus 2 percentage of full scale Tester is protected by a safety disc which ruptures automatically if pressures exceed the upper limits