NALGENE 50 mL Conical Filter Units incorporate a Pall Supor machV polyethersulfone (PES) membrane. Providing vacuum filtration of biological sample volumes ranging from 20 to 50 ml, the filters are attached to a 50 ml centrifuge tube for easy preparation of tissue and cell samples with reduced risk of contamination or spills. The sterilization-grade Pall Supor machV PES membrane with 0.2 μm pore size accelerates flow rates and exhibits low protein binding of cell culture media and other solutions. The filters are gamma irradiated to achieve Sterility Testing Level (SAL) 10^-6. Additional bioburden testing confirms non-cytotoxic and non-pyrogenic status. Units are supplied assembled to a standard 50 ml centrifuge tube and include a sterile closure. Two reusable stands are provided in each case for benchtop use.