20mm Rubber stopper: Standard:ISO and USP standard. Spec.:13mm,20mm,28mm,32mm. Color:grey or red. Yearly output:3.6 billion. Rubber stopper: Standard: ISO and ... USP standard. Spec.: 13mm, 20mm, 28mm, 32mm. Color: grey or red ... :2000, ISO14001:2004, OHSAS18001:1999 standard. Workshop: clean modern workshop. 20mm rubber stopper