Hi Limits Single 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 heater 36" capillary length, 5/16" bulb thickness This 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. Specs: Hi-Limit Application - Generic Hi-Limit Style - Capillary Bulb Diameter - 5/16" Bulb Length - 2-3/4" Capillary Length - 36" Pole/Throw - Single Pole Single Throw (spst) Hi-Limit Amperage - 25A Electrical Connection - Screw Terminal