Compact, DIN-rail-mountable power supplies range from 2.1 A/100-240 input Vac single-phase to 40 A/400-500 input Vac three-phase. They have a power backup buffer module that supplies standby voltage during brownouts or load peaks for a defined period of time, tolerate ambient temperatures -25 to 70 °C, and have short-circuit, overload, and continuous open-circuit protection. Approvals include UL 508, CSA, IEC and EN.