The high definition Bluetooth stereo clip on receiver and earphone offers clear quality sound. It can be used with smartphone and other media devices that are compatible with Bluetooth 4.0 standard. It has 2 components. The receiver is for transferring audio from your Bluetooth to your earphone wirelessly, you can also answer calls with the built-in mic like a handsfree device. At the back of the receiver, it has a convenience collar clip. The other components is a 3.5mm earphone that plays high quality audio.