The HAT903CSAC240 is a heavy-duty SPDT electromechanical relay from the HAT-900 series designed for high-current switching applications. It features 40A continuous rating on the normally open contact and 20A on the normally closed contact, with silver cadmium oxide contacts on a copper base providing reliable electrical performance. The relay operates across a wide temperature range from -40°C to 105°C (Class F) with a maximum contact resistance of 20 mO and maintains insulation resistance of 10 MO minimum at 500 VDC. It is sealed for wave soldering and washing, allowing integration into automated assembly lines, and carries UL and CSA certifications with some TUV ratings. The relay is ideal for industrial control, power distribution, and switching applications requiring robust performance and high current capacity.