Made by one of the leading manufacturers in the industry, the Topow ST Series step up / step down voltage transformers offer you a safe, reliable, affordable and convenient solution to converting voltages from 110-120 volts up to 220-240 volts, or from 220-240 volts down to 110-120 volts for both home use and industrial applications. The ST-3000 is rated at 3000 watts maximum. It features a heavy-duty cord with a standard round prong plug plus a free American Flat outlet plug adapter. There are a total of two outputs on the front panel. Two are grounded outputs, one designated for 110 volts with a US standard outlet, the other for 220 volts only with a universal outlet. Also uses a protective standard fuse for extra safety. The manufacturer recommends you purchase a transformer that is 25% higher then the wattage you need. You should know that you will never damage your appliance with a higher voltage transformer, however if you buy one that is nor powerful enough, it will not work. Remember to leave at least a 100% slack for the transformer. Using them to maximum capacity will eventually burn the transformer out after prolonged use. Some items, such as laser printers and power tools spike when you turn them on. For these types of situations you need to buy a transformer that is at least 3 times the items capacity.