The Whatman GD/X syringe filter is the ideal choice for the preparation of hard-to-filter samples. Constructed of a pigment-free polypropylene housing with a prefiltration stack of Whatman GMF 150 (graded density) and GF/F glass microfiber media, this filter allows you to filter even the most difficult samples with less hand pressure. GD/X syringe filters can process three to seven times more sample volume than standard syringe filters. Membrane: PVDF. Retention: 0.45µm. Filtration Area: 1.3 sq cm. Diameter: 13mm. Inlet: Female Luer Lok. Outlet: Male Slip Luer. 150/Pack. Whatman #: 6872-2504.