Whatman Puradisc 25 mm Depth PP Syringe Filters, 0.45 µm, 1000 Pack, 6790-2504. Regular Price $1,342.16 Price $1,165.56. Add to Cart. Whatman 6883-2504 GD/X 25 mm Syringe Filter, regenerated cellulose filtration medium, 0.45 um (1500 pcs) Regular Price $3,152.78 Price $2,737.94.