I've purchased and enjoyed many OXO products in the past, and will purchase and enjoy OXO products in the future. This digital thermometer was definitely not one of their finer efforts.
I got to use the thermometer a grand total of 3 whole times before it quit working, and I absolutely could not turn it off. The little on/off button on the top had quit responding, as had the button that switched the display between F and C.
On top of that, I couldn't open the battery compartment to try to see if there was a reset switch. No amount of effort would turn the coin-sized slot enough to get the cover off. All that was accomplished was shredding the plastic.
There are other thermometers out there. Pick one of them.