*** Item does NOT come with an Instuction Manual*** Must be installed by a Certified Electrician*** 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-10.000 is rated at 10.000 watts maximum. It also uses a protective standard fuse for extra safety. The manufacturer recommends you purchase a transformer that is 25% higher than 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 not powerful enough, it will not work. Remember to leave at least a 100% slack for the transformer. 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 item's capacity. This is a very heavy transformer, it should be handled with a hand-truck or dolly. Handles are made of plastic and should not be used to lift the item up.