Minimizes unnecessary transfers by filtering directly into 50mL centrifuge tube. Includes two centrifuge tube stands with each case. Cellulose acetate (CA) membranes provide fast flow rates and low protein binding and are good for filtering cell culture media. Polypropylene centrifuge tube is supplied with an individually wrapped cap for storage. Individually packaged, sterile, certified nonpyrogenic. Expiration date appears on the filter funnel and shipping boxes. Expiration date of the membrane is three years from the time the product is manufactured.