the Shore D Hardness test is also called Durometer Hardness Test. The letter "D" symbolizes the type of durometer used to measure the hardness of a material. It is a dimensionless quantity. It goes between 0 and 100. The higher number of hardness represents the harder material. The resulting depth of a specific indenter is dependent on: Hardness of the material Viscoelasticity of the material Shape of the indenter Duration of the test The indentation reading may change over time. This is due to the viscoelastic behavior of rubbers and plastics. Forever Heat shrink sleeve should be tested according to ASTM D 2240 for shore D hardness test. The shore D hardness is important technical data of heat shrinkable wrap sleeves.