Qooltek Digital LCD Thermometer Temperature Gauge Aquarium Thermometer with Probe for Vehicle Reptile Terrarium Fish Tank Refrigerator(Fahrenheit) Remote wired probe can read temperature up to 3.3 feet away Temperature range: -58F~ +199F Designed to be embedded or can be surface mounted Battery Operated (included) (Aprox 2 year battery life)Size 1"x1.75" Mounting Hole Size 1"x 1.75" (0.5" deep).