When sourcing UF membranes, you must prioritize the Molecular Weight Cut-Off (MWCO), typically ranging from 10,000 to 100,000 Daltons, to ensure precise filtration of bacteria and viruses. The membrane material is critical; Polyvinylidene Fluoride (PVDF) is preferred for its superior chemical resistance and mechanical strength, while Polyethersulfone (PES) offers high flux rates. Additionally, verify the fiber diameter (ID/OD) and effective filtration area, as these directly impact the system's flow capacity and footprint.