Eliminates buzzing noise caused by ground loops in some car speakers and home stereo systems. No external power supply required; this noise isolator helps achieve clear audio by reducing current noise in car speakers and home stereo systems. Compatible with any portable device featuring a 3.5mm jack for use with car or home stereo systems. Compact design takes up minimal space and is easy to carry. Item type: Ground Loop Noise Isolator Interface: 3.5mm Frequency response: 20Hz-20kHz Input: Stereo Size: 59 x 20 x 18mm Material: Plastic Color: Black Package Contents: 2 x Ground Loop Noise Isolators Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the actual item. Measurement may vary by +/- 1-3cm.