(1) Low Expansion Coefficient: 9mm Screw Thread Autosampler Vials are made of clear Type 1, Class A Borosilicate Glass with very low expansion coefficient. Series Autosampler Vial. 3) 9-425 Screw Vials: 2ml sample Vials with unique thread design ensures consistent seal and can be reused, not volatile, easy to use, Amber vial with large writing patch for sample identification.