20µL Universal Fit Filter Tips Racked, Clear, Sterile, Rack Pack, 96 Tips/Rack. Axygen Filter Barrier tips are ideal for DNA amplification and microbiological applications where trace contamination can completely invalidate results. The filter prevents cross-contamination from sample to sample by creating a physical barrier in the tip to inhibit and block aerosols. Every polyethylene filter, free from DNA inhibitors, is inserted into the tip robotically to ensure freedom from nuclease contamination. All Axygen filter tips comply with USP 3127 (Heavy Metal Contamination). They are packaged in sealed-bottom racks with lids to prevent contamination and are available in sterilized form.