No compatibility testing has been performed by the different manufacturers and neither Dive Gear Express, Dive Rite, nor XS Scuba (who also supplies the Thermo brand) recommend mixing components from different brands of valve modules. However, our customers tell us these valves have similar modular port threads and we have no reports of problems with crossbars, H-adapters and port plugs in that regard. The DIN-to-yoke adapter inserts along with the standard knobs, but not the Vindicator or XS Safety knobs, should be interchangeable without issues. Beyond cosmetics, we can also say for certain that some other internal parts of all four brands do have slight differences and are not interchangeable.