Whatman PES Mini-UniPrep syringeless filters, 0.2 µm, translucent housing, slit septum cap, 1000 pack, US503NPEPES . Whatman’s Mini-UniPrep Syringeless Filters combine a membrane filter, autosampler vial, septum, and plunger into a single device to provide efficient sample filtration for Ultra High Performance Liquid Chromatography (UHPLC)/High Performance Liquid Chromatography (HPLC) analysis.