Features: Especially designed for Samsung Galaxy S4 Ultra-thin design compact and light weight without increasing additional weight of the S4. Adding wireless charging feature by piggybacking it on the battery of S4 it works well with any Qi-enabled charger. Easy to use. The receiver can be attached to the the battery all the time and it would not interrupt the normal use of the S4. Specifications: Color: Black Input power: WPC 5W Output: 1000mA Charging current: DC5V/500mA (Max) Charging time: about 5 hrs Reaction temperature: -10 ~ 40'C Working heat up range: below 20'C (ambient temperature below 25'C) Working ambient humidity: below 80% Working life: Charge & discharge above 4000 times Size: Approx. 64 x 55 x 1mm Weight: 5g / 0.17oz