Superior Sound Quality. Wherever life takes you, experience your music with powerful stereo sound and punching bass. The Thunder X is compatible with most Bluetooth enabled devices including Apple products like iPhones and iPods, most Android devices, and other smart devices for simple wireless audio streaming. 8W Total output Offers bold sonic output. Experience your music in full-bodied stereo realized through high-performance drivers. Built-In Rechargeable Lithium-Ion battery Provides extended playback, enables you to stream music for up to 4 hours on a full charge. With a charging time for 2 hours.