CYTIVA WHATMAN, 0.45 um Pore Size, 47 mm Dia, Filter Membrane - 32HJ22|7141-124 - Grainger
Whatman 10406870 Cellulose ME25/21 ST Mixed Ester Filter Membrane, 47mm White Circle with 3.1mm Black Grid Sterile, 0.45 Micron (Pack of 100): Science Lab Filter Membranes: Amazon.com: Industrial & Scientific