Little Giant Incubator Thermometer Kit is specially designed to help you monitor the temperature inside an incubator much easier. This thermometer is Mercury-free so it is guaranteed to be safer to use, plus it is fastened on a clear Mylar sheet to let you view the eggs easily when it is on top of it. The graduation marks are very distinct and can be seen through the window of the incubator so it is easy to read. It is ideal for use with most incubators and egg turners. It measures 4.5 in. wide and 5.5 in. high.