These pipette tip filters act as vents to prevent aerosol back-flown of the pipettor when using air displacement pipettors. Our filters offer protection against cross-linking by isolating the pipette body from the chemicals being drawn into the tips. The pore size on these frits is 30 microns. Our pipette filters are used for a wide variety of applications including PCR, DNA amplification and sequencing, forensics, tissue culture and protocols that involve pipetting vaporous, radioactive, biohazard or corrosive materials. They are available in the standard hydrophobic* and hydrophilic** formulations which are designated with an “L”” after the part number. These parts have a tolerance of ± .005″ on thickness and ± .005″ on diameter. Manufactured in the United States. *Hydrophobic = Fear of water, repels water **Hydrophilic = Filters water