Yep, @rlj there are a number of units which will cut power off if too low or too high for prolonged periods of time, including any Furman unit with SMP, but they are not voltage regulators. To qualify it needs to alter the incoming voltage, instead of just cutting it off if too high or low.
This is not a feature everyone needs, per se. Gear is designed to work reasonably well with a range of incoming power, but if your home power isn't that reliable or you want something that makes sure your gear is fed consistently good voltages a regulator is for you.
