Fiber-based filters for pipette tips are said to better-protect liquid samples and users from aerosol contamination in microbiological-sample analysis than do plastic-based tips. The tip filters are by Filtrona Porous Technologies, Colonial Heights, VA.  They have a uniform fiber alignment and porosity for good air flow and efficient pipetting. The bonded fibers are also more resilient than porous plastic. This slight “give” provides a snug, custom fit, minimizing tip crimping and damage during assembly and maximizing production efficiency. 1.5-micron pore sizes are available.