The plastic box, immersion no well configuration has male 1/2 inch NPT threads.  The sensing element is double encapsulated to avoid sensor failures caused by moisture infiltration.  ACI also standardizes with etched Teflon lead wires and wells must be ordered separately for this part.   Please note that the PB enclosure is rated to 203 degrees Fahrenheit. ACI immersion temperature sensors are designed for HVAC, Building Automation Systems, and light industrial applications. Specific applications include: chillers, hot water systems, tanks, and boilers. NOTE: Welded thermowells are not intended for moving water or high pressure service. Fluid velocity and wake frequency are primary factors in well failure. Machined thermowells should be used in these types of applications.