Polytetrafluoroethylene PTFE Syringe Filters, 0.22um, 4mm, Luer-Lok/Luer Slip, Sterile, 100 per pack, SF18243. Regular Price $118.85 Price $103.35. Add to Cart. Add to Wish List. Tisch Scientific PTFE Syringe Filters, 0.22 μm, 30 mm, Luer-Lok/Luer Slip, Nonsterile, 100 Pack, SF18322.