Suitable for filtering water based solutions. Are you accustomed to 25 mm Whatman PVDF syringe filters? These Millipore 33 mm filters have the same filter element and 20% more filter surface area than a 25 mm filter. These are the highest quality syringe filters on the market and that is why we carry them exclusively. "Radiation sterilized; certified noncytotoxic; nonpyrogenic."