Expower(R) Qi Wireless Charging Receiver Card Coil for Samsung Galaxy Note 4 IV .Note4 Receiver fits discreetly behind your existing original Galaxy Note 4 cover to enable wireless Qi charging with the Expower wireless charger and other Qi charging pads (Qi charging pad is required to charge). Metal coil design can improve conversion efficiency and phone do not get hot when charging Use WPC Alliance certified TEXAS INSTRUMENTS Power Management IC and Korea Material Qi technology can be used with most non-metallic cases and covers under 5mm thick. Tested more than 240 hours to guarantee the receiver can performance very well