Whatman 6875-1302 GD/X 13 mm Syringe Filter, PTFE filtration medium, 0.2 um (1500 pcs) Regular Price: $2,401.25. Price $2,088.05. Add To Cart. Whatman 6875-2504 GD/X 25 mm Syringe Filter, PTFE filtration medium, 0.45 um (1500 pcs) Regular Price: $2,560.56. Price $2,226.58.