The outer wall of the Flex-Tube is made of braided groups of filaments arranged at a specific angle.  Thus, external pressure causes a diminishing of the tube diameter and pore size.  Each Flex-Tube has an internal stainless steel spring to limit the diameter diminution.  Filament material varies with the application.

During filtration, the Flex-Tube is retentive.  Conversely, when bumped for regeneration or cleaning, the Flex-Tube responds to the internal pressure generated by bump stroke, propelling the diatomite and accumulated solids from its surface.

Flex-Tubes have a recommended operating differential of 20 psi and an ultimate of 75 psi.