13mm Screw Thread Autosampler Vials are made of USP Type I, N-51A borosilicate glass, amber Sample Vials with unique thread design ensures consistent seal and can be reused, not volatile, easy to use 4ml Amber autosampler vial,15mm Diameter, 45mm Height, 13-425 screw top Standard Autosampler Vial for HPLC & GC Chromatography, vials can be used