Hi LimitsSingle pole rated at 25 amps with temperature rating set at 121°F. Best results are obtained when the bulb is installed in a dry well or groove tube at or immediately before the heater12" capillary length, 5/16" bulb thicknessThis is a safety device! If it is found to be out of calibration, do not attempt to perform a field adjustment! Replace bad hi limit with a new one