COMPATIBILITY: For Audio Playback: Smartphones, tablets and other devices that support Bluetooth and Bluetooth Smart wireless audio profile [Advanced Audio Distribution Profile (A2DP)] CUSTOMIZABLE EQ: Select the best Sound for different occasions with 4 different presets and a customized tuner. POWER: Rechargeable Lithium-Ion Battery for up to 15 hours of battery life between Micro USB charges. AUD: Maximum Sound Level: 90dBC. Frequency Range: 90Hz - 20kHz. Drivers: Two 2" drivers and two 2" x 4" Passive Radiators.