Whatman 6905-2504 GD/X 25 mm Syringe Filter, polyethersulfone filtration medium, 0.45 um (1500 pcs) Regular Price: $2,560.56. Price $2,226.58. Add To Cart. Whatman 6902-2504 GD/X 25 mm Sterile Syringe Filter, glass microfiber filtration medium, 0.45 um (50 pcs) Regular Price: $203.99. Price $177.39.