Borosilicate Glass KIMAX-51® composition assures the best all around chemical durability of commercial glasses now available for laboratory ware. Complies with ASTM specification E438, Type I, Class B Glass requirements. KIMAX-51® has excellent chemical resistance against Sodium leaching; a factor common in Soda Lime Glass products. These are premium quality tubes with sturdy, uniform bottoms and consistent lengths. Tubes are packed in convenient trays for ease of use on bench tops and in drawers. Trays are shrink wrapped in Plastic film with tubes remaining in constant alignment for protection against in transit breakage and contamination. It is designed from ASTM specification E890.