Use the product for a year every 14 days, so far 25 of 30 times. The battery itself has maintained from the outset not really long, but now the device loses after 2-3 minutes the full power and is completely exhausted after 15 minutes. That would be not so bad, if the device could be operated on socket, you wiw it actually is used to, but once you will be turning on the device power is cut off.