Features: Wireless audio playback-smartphone, tablets and other devices that support Bluetooth V2.1 and up. Water-resistant outer shell to Ipx7, can be immersed in water up to 1m for up to 30 minutes. Quick button press to receive incoming phone calls with mic built-in. Built-in TF card slot, supporting MP3 and WAV audio files. Flashing red safety light, suitable for walking and cycling in the dark. BPA free water bottle, can be detached from speaker for easy cleaning.