The unit is very well put together and it functions in an unobtrusive way, smoothly and quietly adjusting to changes in incoming voltage. As stated in the product manual (but NOT in Furman's advertising) the P1800-AR will stabilize its output voltage to approximately 120 volts **plus or minus 5 volts** In other words, output may range from 115 volts to 125 volts depending on local grid supply. Read more
This is a safe range for most gear. The unit will shut itself off if grid voltages are too high or too low to stay within that output range. Definitely a device worth having if you have to operate your gear in a variety of locations, especially in rural areas or old parts of downtown. Furman ought to beef up its product packaging, though. The product's box material is flimsy and easily broken. I had to return the first one because it arrived so badly damaged that I was concerned about possible interior damage in the unit itself. Studio Economik was very helpful in sorting that out for me. Excellent customer service as always.