Dwyer Magnehelic Differential Pressure Gauge – HVAC Test Instrument + Case Dwyer Magnehelic Differential Pressure Gauge Measures differential pressure / airflow (inches of water column and FPM scale). Includes hard protective case, instructions/manual, and fittings. Great for HVAC balancing, cleanroom testing, filter pressure drop measurement, etc. Made in USA. Works with air or compatible gases only. Condition: excellent — shows little to no use. ✅ Ready to use ✅ Includes accessories
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