The display of the STAB range of products comes with two LEDS of the front panel. Green to mean voltage good and a red to mean input supply voltage is not good.
Both LEDs blink simultaneously- indicated a reconnect delay of either 10sec for TVStab or 3 minutes for FridgeStab
Both red and green LEDs remain on- indicates input supply is either too high or too low and the unit is rectifying it.
Only green LED on- Input supply voltage is nominal and output is equivalent to input.