Oct 29, 2021 · PTFE Syringe Filters, 0.22 um, 4mm, Luer-Lok/Luer Slip, Nonsterile, 200 per pack, SF17504. Regular Price: $172.98. Price $156.44. As low as: $140.80. Description. Description. Whatman 4 mm Puradisc Filters are produced from pigment-free polycarbonate with standard inlet (female luer lock) and outlet (male luer) connections. Options include a