Universal tip compatibility Compatible with the great majority of the pipette available in the market. High quality filter Made of HDPE and without celulose additives, these filters are inert and with pore size 3 to 4 times smaller than many other filters. A great quality filter to prevent cross contamination for researchers working with molecular biology. Certified DNA, RNA Pyrogen free The ExpellPlus filter tips are tested to conform to strict bio-load specifications. Batch certificates are available on request. Low retention polymer The ExpellPlus low retention polymer virtually eliminates liquid retention on the tip, assuring greater repetability and precious savings on expensive reagents.