Whatman 10406870 Cellulose ME25/21 ST Mixed Ester Filter Membrane, 47mm White Circle with 3.1mm Black Grid Sterile, 0.45 Micron (Pack of 100) Made from mixed cellulose esters; economical Specifically for aqueous solutions Hydrophilic, sterile, individually packed All membrane filters have a high-contrast grid (3.1 mm) For use up to 125 degree C