Qi Wireless Receiver Card for Samsung (for Samsung S4) Ultra Slim Qi Wireless Receiver Card for Samsung Galaxy S4 / i9500. Works with All WPC Qi Wireless Charger Dock / Wireless Charging Pad. Charging distance: 3-7mm, Input: Self-adaptation, Output current: 600mA. Working Frequency: 110 - 250 KHz, Charging effeciency: &gt; 72%. No interfere with other functions of the Samsung Smartphone.