The HAT901ASDC12-1 is a heavy-duty SPDT electromechanical relay from the HAT-900 series designed for high-current switching applications with DC coil operation. It features 40A continuous rated contact capacity on the normally open pole and 20A on the normally closed pole, with silver cadmium oxide contacts on a copper base for reliable performance. The relay operates across a wide temperature range from -40°C to 85°C (Class B) or -40°C to 105°C (Class F), with a pull-in voltage of 75% of nominal and drop-out voltage of 10% nominal at 25°C. It provides 2000V AC dielectric strength between contact and coil, frame and contact, and coil and frame, with a minimum insulation resistance of 10 MO at 500V DC. This relay is ideal for industrial control, power distribution, and switching applications requiring sealed construction for wave soldering and automated assembly line compatibility.