Low-Retention, Universal Fit: These sterile filter pipette tips measure 50.46 mm, with a maximum volume of 20 microliters (0.02 ml). The inner surface is hydrophobic, minimizing liquid retention and sample losses. They are universally compatible with most pipette brands on the market. Make Material: The pipettor tips are made from high-quality, transparent polypropylene using a unique manufacturing process. Featuring volume graduation markings, they are manufactured in a Class 100,000 cleanroom environment under ISO13485:2016 and ISO9001:2015 quality management system. High Precision Accuracy: Our 20 uL filter tips are sterile, DNase/RNase-free, and pyrogen-safe, thus ensuring a contaminant-free experimentation and laboratory analysis. The tips are sterilized by gamma irradiation SAL10 (ISO11137)-6, with a tolerable temperature range of -80? to 121?. What You Get: The 20?L filtered pipette tips come in autoclavable, yellow rigid racks (boxes). Each rack contains 96 pipette tips, and each purchase includes 20 racks (1920 tips in total). The shelf life is three years after production. Each rack/case is printed with a lot number for quality check and traceability. Unparalleled Customer Service: At Marathon LS, we pride ourselves on manufacturing high-quality laboratory scientific equipment, having done this for over 80 years. If you have any questions or concerns regarding your purchase, please contact us, and we will gladly assist you.