The RSG Security DH series fire door holders are constructed of the finest materials and workmanship available. The door holder is made of durable die-cast metal and is offered in a high-luster powder-coat finish. Other features include standard dual voltage AC or DC inputs of 12 and 24V, 24 and 120V, and 24 and 220V models. While reducing stocking requirements, model 24120 draws a mere .020 ma. At 24VDC, lowering overall job costs. In large installations, the cost savings can be substantial.