PTFE Disk Filters, 0.22 um, 50mm, stepped barb: 5/16 to 1/2, Nonsterile, 10 per pack, DF15274. Polytetrafluoroethylene PTFE Disk Filters, 0.22um, 50mm, stepped barb: 5/16 to 1/2, Nonsterile, 10 per pack. Regular Price: $44.14. Price $38.38. Quantity.