2.0,3.5mm Aux in,USB powered ,Class D amplifier, 50% higher efficiency,Max ... two Φ40 mm micro drivers to deliver stunning sound. The speakers make use of the high efficiency ... of class D amplifiers to present excellent sound quality.Specification:Power output: RMS 1W*2Driver: ... high efficiency of class D amplifiers to present excellent sound quality. Specifications Drivers: 1.5", 4ΩInput ...