Power. Plug power 2500W power 4000w, be sure before you buy, what kind of power. Once, I bought a microwave oven, but insert the plug cord into outlet, I took a very fine line "stall" Strip. Results and plug "We hereby we" sound, lines are hot, almost on fire! Safety certification. Switching products must be qualified to obtain national certification and meet international trade standards. Domestic products through 3C certification and ISO9000 series certification, a number of international brands also won other national and international safety certification, which will pass in the labels on the product, packaging or instructions.