The Lithium-ion rechargeable battery pack attaches to the HEOS 1 base, with easy twist-on/twist-off attachment. Listen to your favorite tracks wirelessly via the included Bluetooth USB connector - no wired or Wi-Fi connection needed. The included silicone splashguard provides protection against splashing water, making the HEOS 1 the ideal wireless portable speaker for outdoor fun - use it poolside or on the spa deck with confidence. You can also listen to your favorite tracks when your smartphone is connected to the HEOS 1 and charge your device at the same time - perfect for those times when you're away from an AC power source and you need to recharge your phone. The USB port provides a 5V/1A output, the same as regular phone chargers.