Durometer
A durometer is a measurement of the hardness of a material, or its resistance to scratching, cutting, abrasion, or indentation. Durometers are expressed using standardized scales that change depending on the hardness of the material, and are defined using a numerical and alpha value. The main two hardness scales used are the Shore hardness scale (Shore OO, Shore A, and Shore D) and the Rockwell hardness scale (Rockwell E, Rockwell M, and Rockwell R). Numerical values for durometers range from 0 to 100, with higher values representing greater hardness.