Centrifuge filter devices are fitted inside centrifuge tubes to filter out sample particles during centrifugation processes. Filter Devices are available in various materials, sizes, and concentration specifications. Disposable ultrafiltration centrifugal devices with a polyethersulfone (PES) membrane, Thermo Scientific™ Pierce™ Protein Concentrators PES may be used with biological samples for buffering exchange, concentration measurement, and desalting.