The dual scale temperature gauge with integrated forged brass fitting and 1-1/2" dial is compatible with similarly sized Webstone products, including Air Separators, Differential Pressure By-Pass Valves, Magnetic Boiler Filters, and Thermostatic Mixing Valves. Monitor temperature readings at key locations, such as near an appliance or within a closed loop. Designed for use with water, oil, glycol mix in residential or commercial residential plumbing, commercial plumbing, heating systems. For temperatures between 32-248°F.