OPTI-UPS TS2000E (2000va 1200w) 3 Year Warranty Line Interactive UPS Battery Backup & Surge Protector AVR Automatic Voltage Regulator, Uninterruptible Power Supply *Requires 20-AMP Outlet See Picture

presumably the batteries will last a long time on a small load. Keeps power stable, and keeps the voltage it should be 100% of the time. Backup feature transitions nicely with no power cuts.

so far it has worked very well , but need to check for any settings . not all backup's will have them . I can only give 4 star because I need to see how long it will last .

We have had 2 power surges, one was bad. We have two units, one on the computer, Printer etc. and one on the media center. Both worked as advertized. Very satisfied with the product.

I have not had to push the limits of time of this backup, but it seems fine. I tested it for a few minutes... I have tried and not been successful in getting the computer to "see" it so it can auto shut down the computer if I am not present during a power outage. Not sure what the problem is and don't have the time or interest in trying to pursue it via tech support. It hooks up via serial cable. I would think a modern appliance would use USB and be more reliable. I am running Win XP Pro. I do like it though because of the size (time it's supposed to run on battery power) for the relatively low price.

as advertised

I bought this unit in 2006 and it served me quite well for about 5 years. It is better than your average UPS because it detects abnormalities in the power and can "boost" or "buck" what is there without fully switching to battery mode. I have seen it do both. It also switches on/off fast enough that I don't even hear blips in my computer's sound. I also seem to remember it being marketed as producing sine waves, but I can't find that detail anywhere now. In about 2011, I noticed the battery life was getting quite short, and recently any slight power fluctuation would cause the entire unit to turn off completely. I pulled the batteries and tested them, and they won't hold a charge at all. They cost anywhere from $17 to $33, and the unit requires 2. I'm in the process of getting new batteries, and I expect the unit itself is still working fine. I suppose 5 years is fair for an AGM battery, but I also notice they are connected in series, so the UPS is working with 24V and can't individually float-charge the batteries. (I think the lifespan would be better with individual monitoring, or if the UPS ran off 12V internally off one larger battery.)