Eliminates buzzing noise caused by ground loops in some car speakers or home stereo systems. No external power supply required; this noise isolator helps achieve clear speech and music by reducing current noise in some car speakers or home stereo systems. Compatible with any portable device that has a 3.5mm jack, for use with car o or home stereo. Compact and lightweight design that saves 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 Note: Light reflection and different display settings may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3cm.