Yarn Package Hardness Tester HP-5. Textile hardness tester (durometer) to determine winding density of loosely wound bobbins of synthetic fibers and closely wound natural fibers, yarns and threads. Indentor - ball diameter 5 mm. The measuring force is according to shore A regulations. Durometer with curved working face for bobbins with diameter up to 400 mm. Brand: SCHMIDT, Origin: Germany.