This document specifies a method for determining the indentation hardness (Shore hardness) of vulcanized or thermoplastic rubber using durometers with the following scales:
—          the A scale for rubbers in the normal-hardness range;
—          the D scale for rubbers in the high-hardness range;
—          the AO scale for rubbers in the low-hardness range and for cellular rubbers;
—          the AM scale for thin rubber test pieces in the normal-hardness range.



ISO 48-4:2018

Rubber, vulcanized or thermoplastic - Determination of hardness - Part 4: Indentation hardness by durometer method (Shore hardness)