Product Name. 28415241. Mixed Cellulose Ester Filter, ME Range (ME 24), 3.1 mm white/black grid for membrane-butler, 0.2 µm pore size, 47 mm circle (400 pcs) 28415242. Mixed Cellulose Ester Filter, ME Range (ME 24), 3.1 mm white/black grid for membrane-butler, 0.2 µm pore size, 50 mm circle (400 pcs) 28415185.