Clip to your visor for hands-free talk while driving, then bring inside to continue the conversation. May be paired with multiple Bluetooth-enabled phones, headset, MP3 player or GPS (not included). With voice prompts, full duplex sound, adjustable volume, noise reduction and echo cancellation; audio streaming and micro USB port. 25 hours talk time/50 days standby on full charge. Includes vehicle charger and USB cable. 2 1/2" w x 4 1/4" h x 1 3/4" d.