KIMBLE® KIMCOTE® Screw Thread Culture Tube With Unattached Cap manufactured by DWK Life Science is made from 33 expansion, low extractable borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class A requirements. The uniform wall thickness allows maximum heat transfer and chemical resistance. KimCote safety coating reduces the hazards of shattered glass and leakage of toxic or hazardous materials.