Corning square bottle-top vacuum filter systems support a higher capacity polyethersulfone (PES) membrane for greater filtering performance. These new bottle/filter systems are designed for filtering and storing cell culture and/or tissue culture media, biological fluids and other aqueous solutions. â€¢ Fits plastic or glass media bottles with 45mm neck sizes. â€¢ Polyethersulfone (PES) membranes provide the fastest flow rates, the lowest protein binding and low extractables and are best for filtering cell culture media. â€¢ Angled hose connector simplifies vacuum line attachment. â€¢ Individually packaged, sterile and certified nonpyrogenic. â€¢ Each system has the membrane material and pore size printed on the unit and is color-coded by membrane type for easy product identification. â€¢ Expiration date appears on the filter funnel and shipping boxes. â€¢ Expiration date of the membrane is three years from the time the product is manufactured.