INSMA Updated Bluetooth 4.0 Audio Receiver Board Wireless Stereo Sound Module DIY Audio Stereo AMP Board for Car Phone PC DC 6~30V Size(L*W*H):55 x 50 x 10 mm Frequency response: 80Hz~22KHz Bluetooth Specification:Bluetooth V3.0+EDR,Support Bluetooth 4.0 Transmit power: Class2 Sound balance:2db Handsfree protocol:1.6 SNR:80dB Transmission distance:10~20M(open area) Using picture-board design, up to 4 shelves full effect SMT precision industrial processing Wide voltage conversion module Bluetooth 6V~30V with anti-reverse design allows DIY frends without pressure