The ToolPRO Infrared Thermometer is a fantastic option for the handyman looking to perform simple diagnostics without having to tear a system apart by allowing you to check temperatures of components from a distance. This non-contact thermometer uses optic sensors that collect heat emitted by objects to give you a simplified average surface temperature. Celsius/Fahrenheit switchable readings make it easy to get an idea of system health regardless of the method by which you measure, with automatic temperature hold capabilities that allow you to freeze the on screen reading for review. The backlit LCD screen ensures that you can clearly read information in any lighting conditions. This lightweight and easy to operate temperature gun utilises a laser thermometer point that shows you the centre point of the radius from which the reading is being drawn, making this the perfect tool for spot checking exhausts, cooling systems, turbos and so much more - a super versatile workshop companion. Measure termperatures between 20-400C with easy, and no-contact safety. The spot to distance ratio of this unit is 10:1. Infrared thermometers measure in a circular pattern, averaging the temperatures of the surfaces inside that circle. A spot to distance ratio of 10:1 means that at a distance of 10cm from the measuring surface, the diameter of the circular pattern that the thermometer is reading will be 1cm in total size. To ensure an accurate measurement it's best to get as close as is practical and safe to the point you are trying to measure. So the further away you are the less accurate the reading will be.