LONG PLAYTIME - Built-in rechargeable 4000 mAh lithium-ion polymer battery. Provides extended playback, enables you to stream music for up to 10 hours on a full charge. (Playtime varies by volume level and audio content).
WATER RESISTANT AND SAND-PROOF DESIGN - Safeguards the subwoofer sound speakers against water submersion, plus dust and other small particles, so you can listen to music both indoors and outdoors.