Hi, Bought a Vguard VWR400 for 1.5 Ton AC. It is a double booster and works upto 130V. Tested till 140 V and works like a charm. The build quality is excellent. Slightly expensive(4200 Rs) compared to local brands but the quality and reliability makes up for it. Warranty is for 3 years and Vguard helpline is very responsive. Buy this if you are experiencing low voltage in your area. Cheers!