Whatman 6901-2502 GD/X 25 Sterile Syringe Filter, 25mm, 0.2 Micron (Pack of 50) 0.2m; ideal choice for the preparation of hard-to-filter samples Pigment-free polypropylene housing with a prefiltration stack Eliminates sample contamination Allows you to filter even the most difficult samples with less hand pressure Processes three to seven times more sample volume