product description Material: monocrystalline silicon solar panel + PVC Size: folded, 290*170*30mm; unfolded, 700*290*16mm Colour: Black Quantity: 1 piece Power: 21 watts Output interface: dual USB Output current: 3500mA (peak current) Conversion efficiency: 19% Output voltage: 5V+0.2V Package Contents: 1*Solar Charging Board 1.High Energy ConversionUses the high-density monocrystalline silicon solar panels convert up to 29%.Tap into the suns radiance and power your devices anywhere,Easily capture every ray of sunshine for you.If you have more than one of the same product, you can connect the DC interface with the donated DC cable to superimpose the output power in series. 2.Extensive compatibilityThe extensive compatibility enables it to charge most electronic products, in the sun for mobile phone/tablet PC/laptop/mobile power supply /PSP/MP4/GPS/ Bluetooth headsets and other electronic devices.Our USB ports and DC port, It can also charge car batteries and accumulators,plus the wide compatibility of the port, are enough to meet your charging needs in the outdoors 3.Smart charging technologyBuilt-in smart chip smart identification of your device, and according to different devices to provide the best charging speed.Safe charging, with overcharge, overheating, short circuit protection 4.Easy to carryThe small size design that can easily squeeze in your backpack offers portability and simplicity, and the attachment hook makes it ideal for connecting to a backpack while youre on the hiking or walking around town.Product adopted special surface protects it from occasional rain or wet Fog and the ports are covered cover to protect them from dust or water damage. 5.Wide range of applicationsYoure outside travelling, hiking, fishing or trekking so your devices never run out of power while there is sunlight.