ST Power Transformer can be used in 110 volt countries and 220 volt countries. ST Power Transformer will convert from 220/240 volt to 110/120 volt AND from 110/120 volt to 220/240 volt. * Input voltage can be changed according to the user. * Suitable for Water Dispenser, Printer Rice Cooker, Fan, Fax Machine, Air Machine, Computer * Input voltage: AC 110v or 220v * With fuse protector or with over current protector *Output voltage: AC220v or 110v Electrical appliances: Apply to all kinds of household electrical appliances, such as rice cookers, Vitamix, coffee machine, soybean milk machine, juicer, and other food cooking machine; Audio power amplifier, printers, fax machines, electric tools, hairdressing tools, applicable working voltage is 110 v or 220 v electrical appliances use. Selection Notice: Transformer cannot be full or over load used,if keep full or over load for a long time , it will lead to the transformer body over-heating, which will affect the service life, and even destroyed transformer directly. Therefore, When you choose transformer,you should make sure the power of transformer must be 1.1~1.5 times larger than your equipment,;for 24 hours continuous work for a long time,you should choose twice the power transformer.so as to ensure the safety and stability of transformer,and prolong its service life. Before you buy the transformer, you can check your appliances, any electrical appliances product labels "power"Or "consumption" logo, in order to confirm the minimum power of transformer to fit your appliances. If you still have doubt ,just contact us with trademanager or leave a message on service center.we will give you the right advice or refer to the following instructions: If the power of equipment is 200w~400w, it must match 500w transformer or above;If the power of equipment is 400w~800w,it must match 1000w transformer or above; If the power of equipment is 800w~1300w, it must match 1500w transformer or above;If the power of equipment is 1300w-1800w, it must match 2000 w transformer or above;If the power of equipment is 1800w to 2400w, it must match 3000 w power transformer or above.