Order Numbers (0.2 um PTFE membrane, 1/8″ NPT threaded inlet/outlet) 17804-NPE Sterile packs of 12. 17804-NPG Sterile packs of 25 For smaller volume venting (e.g. ampoules) 16596 HYK 26 mm 5.3 cm2 Minisart HY, sterile pack of 50, 0.2um PTFE membrane, MBS housing