PMP cylinders produce no meniscus to confuse readings. Guaranteed to meet accuracy requirements of ASTM Class B, E1272, "Cylinder, Graduated, Laboratory, Glass" and all requirements of ISO Standard 6706 "Plastic Laboratory Ware-Graduated Measuring Cylinders ( except sizes -2L and -4L)." Large blue base prevents tipping. All sizes have generous pour spout. Can be chemically sterilized without affecting accuracy. Can be autoclaved, but accuracy will be affected. NOTE: Graduated cylinders are suitable for food and beverage use. PMP resin meets requirements of CFR 21, Part 177.1520.