Hydrophobic Vent Tube Caps attach to the opening of the Stevens SDX Pressure Sensor vent tube. The caps have a hydrophobic membrane that allows barometric pressure compensation without allowing water ingress, while also not requiring replacement. Unlike desiccant cartridges, this cap does not “pull” moisture out of the tube. If there is moisture in the tube already, it will remain there with the use of this cap. It is recommended that each SDX vent tube is protected from water ingress with either this cap or a desiccant cartridge (T-SDX-93030-010).