Highly retentive hydro-phobic PTFE membrane filters that have been specially designed for critical applications. The PTFE membrane in an all-polypropylene construction provides excellent chemical compatibility and superior flow per unit area as compared to other membrane cartridges. No adhesives, binders, or surfac- tants are used in the manufacturing process and all cartridges are rinsed with high-purity water to reduce extractables and downtime. The naturally hydrophobic PTFE membrane is ideally suited for aggressive chemicals such as acids, bases, and solvents. In addition, the hydrophobic membrane provides superior flow and pressure drop characteristics per unit area for gas filtration and tank venting applications. All filter cartridges are 100% integrity tested to ensure filter performance each and every time out of the package. PureFlo PTFE filter cartridges are well-suited for critical applications where superior flow and particle removal efficiency at 0.1 and 0.2 micron is required.