Borosilicate Glass Fermentation Test Tubes are made of 3.3 borosilicate glass,uniform wall thickness for maximum heat transfer,used for bacterial culture,and also be used in medicine,the pharmaceutical industry,yeast plant,ethanol plant on high-carbohydrate yeast assay,or for sugars(alcohol or glycoside)fermentation tests. ● Material:3.3 borosilicate glass ● Color:Clear ● All closures are fully autoclavable ● High temperature and pressure resistance ● Diameter is thin and short ● Tubes feature well-rounded bottoms and fire-polished tops free of rough edges,uniform wall thickness