Check the listing for details. BESIGN Bluetooth Ground Loop Noise Isolator for Car Audio/Home Stereo System .... Condition: New. Listed at 19.39 USD. BESIGN Bluetooth Ground Loop Noise Isolator for Car Audio/Home Stereo System with 3.5mm Audio Cable Product Details Size: 1Pack Brand: BESIGN Connectivity Technology: Bluetooth Input Device Interface: Bluetooth, 3.5mm Jack Power Source: Battery Powered Package Dimensions: 3.31 x 1.46 x 0.94 inches Item Weight: 1.13 ounces Item model number: GLNI01 Is Discontinued By Manufacturer: No Date First Available: March 19, 2017 Manufacturer: BESIGN Ground loop filter noise isolator, eliminating the hiss, buzz and interference 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. You can enjoy the clean and clear music/audio by eliminating the current noise in some car speakers / home stereo systems. Works with any device that has a 3.5mm jack including smartphones, tablets, mp3 player, speakers, when grounding issues persist. You could also use with a Bluetooth Receiver/Bluetooth Hands-free Car Kit in your Car Audio System/Home Stereo. Being so mini, portable and light, plug and play, no battery need or button, all you need to do is to plug in the ground loop isolator Portable, light-weight and plug and play without any complicated setup. Package Contents: Besign Ground Loop noise Isolator with 3.5mm Audio Cable, User Manual.