Harman Kardon Onyx Wireless Speaker System with Rechargeable Battery Four drivers and dual passive radiators deliver incredible sound Numerous wireless connectivity options including Bluetooth with NFC, AirPlay for Apple and DLNA for Android and Windows Optional Harman Kardon Remote app makes connecting your device easy while giving you complete control over the audio settings Built-in, rechargeable battery delivers up to 6 hours of playback while letting you enjoy your music anywhere you like,Power Requirement: 4 x 15W Sophisticated and elegant design uses premium materials like stainless steel and real leather