4000W High Power SCR Electronic Volt Regulator Speed Controller Motor AC 220V 110V

Item arrived on time, which was good. The picture on Amazon shows the terminals labelled in English, but the actual regulator had a Chinese label which threw me for a moment, but in all other respects looked identical. I wired it into an extension lead (careful not to cut the earth wire - just the live and neutral) and then tested the unit with a table lamp: worked perfectly as a dimmer switch for the light.Next, put it on a 2KW water heater that only had an on/off switch. Again, works as expected: I can now keep the boiler on a simmer once it is up to temperature.4 star rather than 5 because of the Chinese label on the actual item rather than English as per the photo. Otherwise, exactly as described.