Hardness Testers and Durometers

A durometer is a device used to measure the hardness of materials, particularly elastomers, plastics, and other flexible substances. The term "durometer" can also refer to the scale of hardness measured by the device. 

A durometer consists of a spring-loaded pin or indenter that is pressed against the material being tested. The hardness measurement is determined by how much the material resists the indentation. The result is displayed as a number, typically on a scale ranging from 0 (very soft) to 100 (very hard).