Altronix AL400ULXR Power Supply-Charger converts a 115VAC/60Hz input into one (1) Class 2 Rated 12VDC or 24VDC power limited output. These outputs are filtered and electronically regulated. AL400ULXR Power Supply-Charger has got short circuit and thermal overload protection. AL400ULXR Power Supply-Charger automatically switch over to stand-by battery when AC fails (zero voltage drop). It has a red enclosure and is UL/CUL listed.