1.High Energy transfer rate: 21 watt SUNPOWER High efficiency solar panel increases conversion efficiency up to 24% which is much higher than common solar panel charger (≤15%). 2.Unlimited Power Source : Simply unfold under the sunlight and make full use of the clean and unlimited solar power to charge your smartphone or any other USB powered devices. Featuring two Smart charging ports, you can charge any two devices at once. 3.Portable and Lightweight: Triple fold design (71*29*3.5CM) and lightweight (764g) make it very easy to pack into your backpack. Well-placed eye-hole, mounting loops around the panel allow easy attachment to backpacks, bicycle, tent, etc. 4.Renewable Power Source Anywhere Anytime: Simply unfold PowerGreen lightweight solar panel charger and enjoy clean and unlimited charging experience straight from the sunlight. 5.Charge Fast, Charge Smartly : Intelligent chip inside will automatically detect fastest possible charge currency for your device and SUNPOWER solar panel will offer up to 24% high conversion efficiency to achieve high speed charging. What’s more, you could charge two devices at the same time via DC & USB port. 6.Take it Wherever You Go: Ultra-portable and convenient, the Tri-fold design is perfect for outdoor activity, e.g. hiking, traveling, etc. Evenly placed eyeholes and mounting loops attach easily to your backpack. In addition, the industrial grade PET panels are bound by heavy-duty polyester canvas, making this solar charger water-resistant. Note: 1. Due to the intensity of sunlight, the charging to your mobile often is not very stable. 2.To ensure best performance, we strongly recommend to charge your device with original cable or a third-party certified cable. 3. It will not work well in cloudy days.