Ahh. Uninterruptible Power Supply -- most commonly used with computers. It plugs into the wall, you plug your equipment into the UPS, then when the power cuts out in your house the equipment plugged into the UPS keeps running for a while (until the battery in the UPS runs down).

Mostly to get you through those short outages which crash your computer and make your VCR say 12:00

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8