Single pole rated at 25 amps with max temp rating at 107?F. Best results are obtained when the bulb is installed in a dry well or groove tube at or immediately before the heater. This is a safety device! If it is found to be out of calibration, do not attempt to perform a field adjustment! Replace bad thermostat with a new one. Electrical Connection: 1/4" Male Slide Connector Bulb Diameter: 5/16" Bulb Length: 4-1/8" Capillary Length: 48" Amperage: 25A