Specification: Material: ABS Dimensions: 15x15x7.1cm Weight: 88g Input voltage: 9V / 2A Power: 10W Working distance: <5mm Charging efficiency: 70%-76%Qi is one of the most modern wireless energy transfer methods using inductive charging. It is designed for smartphones equipped with this technology. The basis of the system is the phenomenon of electromagnetic induction between two coils. The charger has a power transmitter that contains an oscillating magnetic field generating coil and an alternating current inducing magnetic field in the smartphone.