... used in Air Compressors,Hollow Pumps,Air-Pressure Piping,Pressure Regulating Valves,Testing Equipment,Medical Sterilizers,etc ... / 3" (80mm) / 4" (100mm) / 6" (150mm)3. Pressure Range: vacuum, compound, 0 - 15psi - 10,000psi (customer-made ... pressure range)4. Connection: Bottom (Vertical), Center Back ... 1% 8. Window: glass, polycarbonate Pump Pressure Gauge