Ametek Crystal M1 [M1-30PSI-BHX-E-W] Digital Pressure Gauge, 1/4" NPT male, 0 to 30 PSI w/ Pump System B (Pneumatic) -0.91 to 40 Bar, No Liquid (Drained) & Waterproof Case. The Crystal M1 Pressure Gauge maintains 0.2% of reading accuracy from -10˚ to 50˚C. Accuracy is not affected by dropping, over-pressure, vibration, temperature, or rapid pressure change.