Built in Li-ion battery, rechargeabe via USB cable.      Micro 5Pin                                                                         
LED for bluetooth connection                                  
Bluetooth V3.0, support Apple / windows  system                                                       specification ﹕
A. Working  frequency: 2.400GHz-2.483GHz
B .Working distance: 10m
C.Battery: :180mAh Polymer lithium ion battery (3.7V)(volume:180MAh)
D.Charging time: 2 hours, Uninterrupted working time: 100-hour                                                          
E.Standby 90 days
F. Working current: <2mA @ 3V
G. Sleeping current: <50uA @ 3V
H. Sleeping mode: The keyboard automatically enter sleep mode when you are not using in 20 minutes.
I. Sleeping waking way: To press any key