Description General description • Conforms to ISO 4142 • High quality test tubes designed and constructed for optimum performance • Manufactured from Pyrex borosilicate glass which gives superior performance to neutral borosilicate and soda-lime glass • Allows use at high temperatures - up to 500°C • Ideal for microbiology culture work • Excellent resistance to chemical attack Legal Information PYREX is a registered trademark of Corning, Inc.