Eliminating Buzzing Noise : Completely eliminating the buzzing noise, caused by ground loops which happens when the audio source and the speaker use the same power source in some car speakers / home stereo systems when using the Bluetooth receiver. WORKING PRINCIPLE : The working principle of this noise isolator 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, for your Car Audio System/Home Stereo, when grounding issues persist. Also used with a Bluetooth Receiver/Bluetooth Hands-free Car Kit in your Car Audio System/Home Stereo. COMPACT AND 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. NOTE: The Ground Loop Isolator connect to the AUX Jack in car to noise.You enjoy sound when use it with Ground Loop Noise isolator. Connection Instructions: Connect GROUND LOOP NOISE ISOLATOR between speaker and Bluetooth 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. Completely eliminating the buzzing noise caused by ground loops which happens when the audio source and the speaker use the power source Colour: Black Material: ABS Size: 11x7x3cm Package Contents: 2 * Noise Isolator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.