We also offer sample membrane filters that are readily available and ship from stock in one business day. Whatman Nuclepore Hydrophilic Membrane, 0.2 µm Pore Size, 47 mm Circle, 100 Pack, 10417012 Regular Price $173.86 Price $150.98 Add to Cart Whatman 7182-002 Cellulose Nitrate Membrane Circle, plain, 0.2 um pore size, 25 mm, 100 per pack