UltraCruz^® Filter Flask supplied with polyethersulfone (PES) membrane is ideal for large volume sample separation and purification in a laboratory. UltraCruz^® Filter Flask with PES comes with a bottle top filter and solution bottle as a unit, suitable for sterile vacuum filtration applications. With low protein binding and low extractables, it can separate and purify liquids such as cell culture media, serum, and HPLC solutions. Filter Flasks are sterilized by gamma irradiation making them nonpyrogenic, noncytotoxic, and RNase/DNase free. The low liquid retention funnel design and polyethersulfone (PES) filter membrane provide a rapid flow rate. This filtration system also has engraved graduations on the filters and bottles that allow for precise work. Made from high quality polystyrene, the solution bottles feature a heavy-walled construction for added strength and two indents for a secure grip. An easy to open textured cap is included as well. Filter Flasks are manufactured from U.S. Pharmacopeia (USP) class VI virgin polystyrene in a class 100,000 cleanroom. Class VI is the most rigorous testing aimed to certify that there are no harmful reactions or long-term bodily effects caused by chemicals that leach out of plastic materials. Class 100,000 cleanrooms are allowed a maximum of 700 particles per cubic foot greater than 5 microns and less than 100,000 particles per cubic foot greater than 0.3 microns. They must also have at least 20 air changes per hour. This classification is closest to ISO-8 by the International Organization for Standardization.