Nalgene DS0320 Reusable Polysulfone Bottle Top Filter Holders offers the cost savings and waste reduction of a reusable filter housing. The deep threads screw securely onto the bottle for convenient filling and vacuum filtration. The filters feature a removable sterilization membrane support plate designed to provide maximum flow rate and throughput, as well as a vacuum port on the lower half of the assembly and molded-in graduations. The polypropylene tubing adapter can be stuffed with cotton for sterile venting during autoclaving. Polysulfone is strong, washable and autoclavable.