Manufactured in a precision molding facility from 100% virgin polypropylene, United micropipette tips are DNase, RNase and Pyrogen free. The highly smooth surface is hydrophobic to provide low liquid retention, increased accuracy and repeatability. Inner radial rings enable an airtight grip on the tip cone. Autoclavable at 121°C and 15 psi for 30 minutes.United tips are compatible with many leading brands of pipettes, such as Eppendorf, Gilson, and Rainin. Please call for a complete list of compatible micropipette models.