Core – is a cardboard or plastic spool for winding ribbon rolls, tags, labels, etc. onto it.
Core size – is the internal diameter of the spool. Usually it is indicated in millimeters or inches.
Glossary
CSA
CSA (Canadian Standard Association).
D 2671
ASTM D 2671 – Standard Test Methods for Heat Shrink Tubing for Electrical Use.
D 412
ASTM D 412 – Standard Test Methods for Evaluating the Tensile Properties of Vulcanized Rubbers and Thermoplastic Elastomers.
D 570
ASTM D 570 is the standard test method for determining water absorption of plastics.