High Heat Oven Thermometer. Stop guessing what your oven is reading and know for sure! This thermometer measures temperatures from 100 to 750 degrees F (50 C to 400 degrees C). Thermometer face is approximately 2 1/4 in and has a large red needle for accurate readings. This thermometer has a wide base and a integrated hook for easy use in your oven. Made of stainless steel!