Bacharach MZF Pressure/Draft Gauge 13-7019 - Positive Energy Conservation Products
The MZF gauge (pictured) requires no liquid or tedious leveling. Ideal for residential commercial and industrial heating plants. Can measure furnace draft pressure drop across air filters. Range is +1.0 to 0 to -5 mm W. Other models available. Comes with a 5″ draft tube and 9′ of rubber tubing.