This product is a relay-type high accuracy household voltage stabilizer. Using it can regulate the big range fluctuating voltage into a general voltage output. An ideal stabilized power source for modern household purpose. Safe and reliable. Large range of stabilization. Input voltage: AC 80v-260v output voltage: AC 220V+/- 5% or AC 110v+5% with over current protector. With display of output voltage. . Remember to leave at least a 100-percent Margin for power surges/Spike when buying a transformer. Some items, such as Televisions, computer monitors Spike when you turn them on. For these products you need to buy a voltage converter transformer that is at least 3 times the items capacity. Power tools, laser printers and heating appliances like coffee makers, toasters, microwaves, Halogen, fluorescent bulbs you must leave a Margin of 3-4 times.