polypropylene housing ptfe membrane filter 0.22 um Advantec PVDF Syringe Filters, Advantec, 0.22 Micron, 30mm, 50/Pk - Sterlitech 0.22µm (0.20µm), 13mm, Abluo, 0.76, 50, Polypropylene, 18, FLL, MLL, 5.0 Q: Does the syringe filter size refer to the outer diameter of its housing?