Tensile Set (Elastomers) ASTM D412 - Intertek
ASTM D 412 specifies a dumbbell shaped specimen. The specification describes 6 options for the sample dimensions, but the preferred sample is "Die C". Die C has an overall length of 115mm (4.5 inches) with a narrow section 33mm (1.31 inches) long. This provides a gauge length (benchmark) 25mm (1 inch) long and a gauge width of 6mm (0.25 inch).