It has multiple circuit protection systems, can avoid over charging, etc. 2.Popular: Fashionable, durable, colorful, portable, useful, etc. 3.Good quality: All our products would be strictly tested before delivery. 4.High efficiency: Power efficiency > 90% , energy-efficient and environmentally friendly. 5.Convenient: Charge your mobile phone anywhere, anytime Specification: (1)Battery Type: Lithium-ion battery (2)Battery Capacity: 20800 mAh (3)Additional Features: All Phones Incl iphone 5, 5S, 5C (4)Power Output:20800 mAh5V (5)Power Input: 110V-240AC , 5060 Hz (6)Charging & Stand-by Time: 12 Hours (7)Output Voltage: 3.5V 5.0V (8)Compatibility: Samsung, Nokia, IPhone, IPad, HTC, Blackberry, MP3 & MP4 Players (9)Input Current: 100240V 0.15A