Calibrated "to deliver" (TD) at 20°C, these borosilicate glass pipettes have a permanently colored amber scale with the zero line at the top. The small amount remaining in the tip after completion of free delivery is blown out and added to the main delivery volume (ground band indicator at top). The 5,10, and 25mL pipettes have openings of reduced diameter. Reference: ASTM E 1044, Lab Grade NOTE: Do not pipette by mouth. A mechanical device is suggested. Scientists rely on the expertise and artistic skills of Wilmad-LabGlass' engineers and glass specialists to manufacture NMR and EPR consumables and laboratory glassware of the highest quality. Used daily in academia, healthcare and chemical, petroleum and other industrial applications, Wilmad offers 7000+ items as part of their standard catalog as well as custom fabrication for individual glassware, glass repair services and OEM glass parts.