Features: ELIMINATING NOISE: Completely eliminating the buzzing noise caused by ground loops which happens when the audio source and the speaker use the power source. WORKING PRINCIPLE: The working principle of it is to achieve a clear speech / music by eliminating the current noise in some car speakers / home stereo systems. COMPATIBLE MODELS: Works with any portable device that has 3.5mm audio jacks, suitable for Car Audio System / Home Stereo. Also used with a BT Receiver in car audio system. COMPACT & PORTABLE: Being so mini and light-weight (2.01*0.59*0.59 IN, 0.99 OZ), this little gadget does not take much space and can be easily taken away. ENJOY CRYSTAL SOUND: The Ground Loop Isolator connect to the AUX Jack in car to eliminate noise. You will enjoy good quality sound when use it. Specifications: Color: Black Frequency Response: 20Hz-20kHz Jack: 3.5mm Package Size: 7.5*4*2cm / 2.95*1.57*0.79in Package Weight: 36g / 1.27oz Connection Instructions: Connect GROUND LOOP NOISE ISOLATOR between speaker and BT receiver with dual 3.5mm audio cable or 3.5mm to R C A audio cable as the following Picture shows. Note: It can use from both sides, no direction limited, just plug one jack as input, the other is output. Package List: 1 * Noise Isolator 1 * 3.5mm Audio Cable