A couple of days ago, I hunted for two hours in 15 F degrees or -9 C for a test of my preparation for cold weather. I found that I need improvement on my hands, head and equipment. I was using a pair of heavy ski gloves and the hand that was holding the detector was cold to very cold most of the time. With the free hand I moved my fingers out of their place in the glove to the palm area and they would warm up. This tells me that I should be using mittens rather than gloves. My head was covered with a loose fitting wool cap that moved around with the hood on my coat and that was annoying. My face was cold most of the time. After an hour, my Pro Pointer would stay on for just seconds before it would give the low battery sounds. So, obviously, it needs to be kept warm. The only thing I noticed with the AT Pro was that the battery indicator dropped one notch soon after beginning the hunt. John and others, it would be helpful to read and see your protection methods to allow you to hunt for longer periods of time in colder weather.