These filtered pipet tips feature special hydrophobic porosity filters with fluorocarbon resin that includes PTFE. Sterilized filters contain fluorocarbon resin with PTFE dense, hydrophobic porosity filters excellent chemical resistance easy sample Collection these filter tips prevent sample overflow when aspiration occurs due to human error or contamination occurs due to aerosol and DNA. They are dense enough to prevent overflow, but they maintain the holes in the filters. The filter tips prevent the sample overflow the minute after the solution is absorbed. Empty racks are available separately.