Western Blotting Filter Paper, 0.83 mm thick, 8 x 13.5 cm Thermo Scientific Pierce Western Blotting Filter Papers, 0.83-mm thick, are pre-cut cotton sheets for wet or semi-dry, passive or electrophoretic transfer of proteins from polyacrylamide gels (SDS-PAGE) to PVDF, nitrocellulose, or other membranes.