Eliminates buzzing noise caused by ground loops in some car speakers and home stereos. No external power supply required; this noise isolator helps achieve clear audio by reducing current noise in car speakers and home stereos. Compatible with any portable device featuring a 3.5mm jack for use with car or home stereo systems. Compact and lightweight design saves space and allows for easy portability. Item type: Ground loop noise isolator Interface: 3.5mm Frequency response: 20Hz20kHz Input: Stereo Size: 59 x 20 x 18mm Material: Plastic Color: Black Package Contents: 2 x Ground loop noise isolators Note: Light reflection and differences in display screens may cause slight variations in the color of the item shown. Measurement may vary by +/- 13 cm.