This is the third CP UPS that I have bought, and the largest. The only reason I did not give this 5 stars is that I don't know how long it will last. The first one I got is a combo surge protector and UPS. The UPS function lasted about 3 years or so. I have mixed emotions about that. I don't know if this is good or bad, but I would have been happier if it had lasted much longer. The latest one I got has a lot more bells and whistles on it (and cost more). Time will tell if I like it.With out a doubt, this unit will pay for itself.