Whatman 10401170, Cellulose Nitrate Membrane, plain, sterile, 0.45 um pore size, 47 mm circle (100 pcs) Regular Price $203.68 Price $176.88. Add to Cart. Whatman 6894-2504 GD/X 25 mm Syringe Filter, glass microfiber filtration medium, 0.45 um (150 pcs) Regular Price $539.90 Price $468.86. Add to Cart.