Are these extenders only compatible with...
Are these extenders only compatible with Tufo tires?
No, they will screw on to any presta valve with threads.I'll add, that while these work pretty well the best is to replace the whole valve core with a longer one, if the valve core can be removed. That method just provides a better seal.
Removable valve cores are the prerequisite to use Tufo valve extenders. The threaded end of the pictured Tufo extender threads into where the core was in the valve stem. Then the core threads into the extender. This solution is the best compared to Topeak or Problem solvers or others cause the Tufo is actually just extending the stem. The others leave the original valve core in place.