Autosampler Vials, Membrane Solutions 2ml HPLC Vials, 9-425 Lab Clear Vials with Write-on Spot and Graduations, 9mm Blue ABS Screw Caps & Septa for GC Sample Vials, 100 Pcs Features : LOW EXPANSION COEFFICIENT – 9mm Screw Thread Autosampler Vials are made of clear Type 1, Class A Borosilicate Glass with very low expansion coefficient.