I rarely write reviews but I had to for this product.Received just yesterday... 2 days earlier then expected!!! Thanks Amazon. I charged the usb for 3 hrs and kept recording mode overnight. The device was still recording (blue light blinking) and I switched it off and checked the files and I had the recording for 12 hrs!!!!!! I will try again after charging for 3 hours and till the blue light stops and see how many hrs can it record Whether the claimed 140 hrs will be true or not. I charge only 3 hrs because I am cautious of overcharging. I am impressed by this device. Previously I had doubts after reading the reviews but now I recommend to anyone for this price.