TRANSFORMER PURCHASE GUIDE This Heavy-Duty Continuous Use Voltage Converter Transformer can be used with both 50Hz and 60Hz. It will step Up a single-phase 110V/120V to 220V/240V single phase, OR Step Down from 220V/240V to 110V/120V. Remember to leave at least a 100% margin for power surges/spike when buying a transformer. Some items, such as televisions and 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 item's capacity. For Power tools, laser printers, and heating appliances like coffee makers, Rice Cookers, Toasters, Microwaves, Lasers, Halogen, or fluorescent bulbs you must leave a margin of 3-4 times the rated wattage. It doesn't hurt to buy a transformer that is rated much higher than the listed watts on your device.