Durometer is the measurement of hardness in polymers, elastomers, and rubbers. The Durometer measures hardness by the penetration of an indentor into the rubber sample. According to the Shore scale, hardness may be defined as a material’s resistance to permanent indention

Shore A

Measures the hardness of flexible mold rubbers that range from very soft and flexible, to medium and somewhat flexible.

Shore D

Measures the hardness of hard rubbers, semi-rigid plastics and hard plastics.