SoundLogic XT LED Wireless Bluetooth Dancing Water Speakers, Black, Pack of 2 Bluetooth 2.1 technology Built-in 3.7V rechargeable Li-ion battery (Input: DC 5V / 0.8A) Frequency Response: 100Hz 18KHz Working Time: 1 to 1.5 Hours (based on personal usage) Charging Time: About 2 Hours