Whatman 7182-009 Cellulose Nitrate Membrane Circle, plain, 0.2 um pore size, 90 mm, 25 per pack. Regular Price $139.40 Price $121.06. Add to Cart. Add to Wish List. Whatman PTFE Mini-UniPrep syringeless filters, 0.2 µm, translucent housing, slit septum cap, 100 pack, US203NPEORG. Regular Price $284.54 Price $247.10.