Main Features: ' Material: aluminum alloy, stainless steel ' Power: 15.5W ' Port: 2 USB charging ports ' IC: intelligent identification IC ' Compatible with most 5V electronic devices on the market including cellphones, tablets, e-books, mini speakers, Bluetooth headphones, MP3, MP4, PDA, PSP, GPS ' Protection system: over current protection, over voltage protection, short circuit protection ' Solid structure makes it an emergency hammer under special conditions, to break the window and keep you safe