Tappetini in gomma

The designation "Sh-A" or, alternatively, "Sh-D" stands for Shore Hardness, which is a scale of hardness for elastomers and plastics. In the case of softer, rubber type materials, the A scale is used, while for harder materials the D scale. The test procedure, which is standardized per DIN 53505 and DIN 7868 (German Industry Norm), consists of a tempered steel indenter, whose shape varies for the A and D scale tests, being pressed into a material with a specific force whereby the amount of penetration is measured. The measuring scale goes from 0 (complete penetration) to 100 (no penetration) - the higher the number, the harder the substance.