1,ERGONOMIC: Solar backpack back with thickened high elasticity breathable sandwich, S shaped back pad design in line with ergonomics, easy to reduce the pressure of the load. 2,HIGH CONVERSION RATE: Solar powered backpack adopts third generation solar panel, with a photoelectric conversion efficiency of 23%‑25%, more than 60% higher than ordinary solar panels. 3,WATERPROOF: Solar powered backpack adopts PVC coated fabric and waterproof zipper to improve waterproof performance. In line with the green concept, there is light and there is power. 4,EASY TO USE: Solar panel backpack has multiple internal compartments for one key storage, more convenient for travel. Designed with USB interface, sound interface, more convenient to listen to songs and charge. 5,INTELLIGENT CIRCUIT PROTECTION: Solar panel has 9 intelligent circuit protection, overcharge protection, over voltage protection, over current protection, over power protection, short circuit protection, temperature protection, overload protection, reverse discharge protection, static protection. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.