The ASTM D2240 standard is used to evaluate the hardness of a rubber sample with the use of a series of tests performed with a durometer. Hardness is measured when a force is applied to the sample with an indentor under specific conditions. The indentation hardness is then determined based on the elastic modulus and viscoelastic behavior of the sample.
Shore A00
Measures rubber and gels that are very soft
Shore A
Measures the hardness of flexible mold rubber that range from very soft and flexible, to medium and somewhat flexible.
Shore D
Measures the hardness of hard rubber, semi-rigid plastics and hard plastics.