Nov 16, 2021 · 7590-004. PTFE Membrane, WTP Range, 1 µm pore size, 47 mm circle (100 pcs) Parameter. PTFE Membrane, WTP Range, 0.2 µm pore size, 25 mm circle (100 pcs) There are no available product features to display for this product variant. Grade 1 Qualitative Filter paper standard grade, circle, 76.2 mm, 500/PK. Download.