The PreCon Model ST-D* Duct Thermistor provides precision remote temperature sensing for building automation systems and mechanical equipment room instrumentation. The active sensing element is a highly stable precision thermistor material. The sensing element is sealed with a thermally conductive compound in a 9″ (22.8 cm) long 304 stainless steel tube attached to a 4″ (10 cm) electrical strap. The slots in the mounting bracket form mounting ears for direct duct mounting and standard electrical boxes. The grommet on the tube fitting seals a 9/16″ (1.43 cm) insertion hole.