An oven thermometer is a device that measures the temperature inside an oven. It is useful for checking the accuracy of the oven's thermostat, ensuring even heating, and preventing overcooking or undercooking of food. 

A fridge freezer thermometer can be useful for monitoring the performance and efficiency of a fridge or freezer, as well as for complying with food safety regulations and standards.

Pocket thermometers are useful for many purposes, such as checking the temperature of food, water, air, or body. They are easy to carry and operate and can provide accurate readings in seconds.

A deep fryer thermometer can help prevent overcooking, undercooking, or oil fires, and improve the quality and taste of fried foods.

Digital thermometers are more accurate, faster, and easier to use than traditional thermometers that rely on mercury or alcohol. Digital thermometers can be used for various purposes, such as measuring food temperature, room temperature, etc.