The ALTRONIX-SMP3ET is a high current power supply/charger that converts a low voltage input to a 6 or 12VDC output.The built-in charger keeps gel and sealed lead acid backup batteries charged to full capacity. In the event of a power outage, the SMP3ET automatically switches over to backup battery power. The unit is housed in a grey, wall mount enclosure.This power supply/charger is typically used in access control, security, and CCTV systems where additional power is required. Also known as -40VA Plug In Step-Down Transformer-Altronix Corp. SWTG PS 6-24VDC @2.5A ENC&XFMR - AX-SMP3ET