OFF (open) at 120 deg F (48.9 deg C) water temperature and ON (closed) at 100 deg F (37.8 deg C) water temperature thermostatic switch modes|Bimetal, senses surface temperature of outside diameter of pipe thermostatic element|AQS-1/2 clips onto 1/2 in copper pipe or 3/8 in steel pipe (OD of pipe 5/8 in) and AQS-3/4 clips onto 3/4 in copper pipe or 1/2 in steel pipe (OD of pipe 7/8 in) pipe size|Mounting: May be installed to sense temperature at the suction or discharge pipe of the pump|Epoxy (Environmentally Sealed) thermostat covering|Stainless steel pipe clip|Bimetal sensing element|Insulated 18 in (457 mm) No 18 AWG wire leads|Connects to the lead wires in the connection box of any Bell and Gossett NBF/NRF/SSF circulator|Provides thermostat control to the circulator and It will turn OFF (open) at 120 deg F (48.9 deg C) water temperature and ON (closed) at 100 deg F (37.8 deg C) water temperature

UL Listed