Coaxial cartridges are used for 2 component systems such as composite mortar. In this case, the two components are arranged parallel to one another. The B component with the lower volume fraction is located in a tube in the center of the larger outer tube. A special ejector is required to press out these cartridges. This applies equal squeezing forces to both plungers (sealing bottom of both chambers) and thus conveys both components parallel to each other into the static mixer. As a rule, the mixing ratio of such cartridge systems is 10:1.
Since these cartridges look like 1-component cartridges from the outside, it is important to pay attention to the underside. Here you can immediately see the arrangement of the two components.