A voltage regulator boosts power output when the supply coming in is too low. Unlike surge protectors which only react to that which comes down the line, a voltage regulator continuously monitors the line and uses a built-in transformer to increase voltage to a high enough level to protect equipment down the line. It does this by taking any additional power it receives and storing it for later use.
Easy to read, the LED indicators let you know what is going on, electrically speaking. With each line tracked independently, only those circuits needing extra power get it. You can add an additional surge protector to keep the spikes from getting by and damaging your equipment that way.