Quick Connect Fittings
The Quick Connect (also known as Push to Connect) fittings are used in many of our water filtration products. They work by having a one way locking ring with small metal teeth that grip on the outside diameter of the tubing. The tube is inserted through a tight fitting o-ring to prevent leaks, and the metal teeth hold it into place. The connections are tested for pull out force and typically requires some force to pull out without pushing in the collet, so it would be very difficult to do on accident. The collet works by pushing the teeth out of place and allowing the tubing to easily slide out.
Note: The tubing should last the life of the system, however they should be kept away from any hot air sources to prevent potential embrittlement. Typically this isn't an issue for under the sink applications.