Lightweight, Water-Resistant Removable Speakers: Weighs less than 3 lbs and has a removable 20-watt speaker with compelling design in a water-resistant backpack. Rechargeable Battery + Built in Power Bank Charges Your iPhone / Android / Tablet: The backpack + 15-watt speakers combine to deliver powerful, full-bodied sound that lasts for 8+ hours. Works with iPhone and Android devices seamlessly, and charges them while you're on the go.