Universal Qi Wireless Receiver Film for Android Micro-usb (B4) Ultra Slim Qi Wireless Receiver Film for All Android Cellphone Works with All WPC Qi Wireless Charger Dock / Wireless Charging Pad. Charging distance: 3-7mm, Input: Self-adaptation, Output current: 600 - 850mA MAX. Working Frequency: 110 - 205 KHz, Charging effeciency: &gt;72%. Safe,dust-proof and convenient,don't plug the micro-usb port repeatedly than wired charge,avoid damage the port.