GranVela BV350 wireless Bluetooth stereo speakers bicycle riding bicycle outdoor subwoofer Portable audio card for Phones and Tablets - Blue [Hands-free calls]Support call hands-free, it contains a high definition microphone. Clear call quality and smooth, it can release your hands, while receiving a call while concentrate on driving. [Compatibility]See you there BV350 Bluetooth 2.1 chip, compatible with the current mainstream Bluetooth phones and tablet computers and other equipment, the effective transmission range of 10 meters; and low-power, medium-volume life time of up to six hours under [High-fidelity sound quality level]Micro USB charging port, 3.5mm audio input interface and TF card slot that can support audio file decoding capabilities; worth mentioning is that it is compatible with MP3, WMA, WAV common format; also compatible FLAC, APE lossless formats. [Unique appearance] It looks exactly like an outdoor sports water bottles, volume size is also similar; with one hand can easily hold in your hand [Self protection] The shell is made of TPU environmentally sound plastic wrap, extremely resistant, shock, scratch; fully sealed design makes this sound has a good dust-proof function; the top of the fuselage design hook, easy to hang the sound when the user is out backpack; for those who like outdoor riding for you, is a good choice.