Small size, easy to carry : New power amplifier circuit, high SNR, low distortion : Adopt positive and negative power supply, satisfy with large Dynamic Signal Processing : Electronic volume control : Key lock function : Built-in rechargeable lithium battery, normally works up to 10 hours : Built-in three types of EQ option with different bass effect and a high level option : Standard MINI USB connector : Removable transparent back splint (lean 45 ), to meet different needs