These vials are manufactured from Type 1 Class A Borosilicate glass. The standard flat bottom vials can be used with Hewlett-Packard, Carlo Erba and Shimadzu. The European 20mm aluminum seal vials with rounded bottoms can be used in Perkin-Elmer, Tekmar, CTC/L.E.A.P.™ Technologies, Gertsel® and Varian.