Yes, they are. One of the advantages of the SIMPLEX system is the ability to choose igniter. A Class 3 igniter should be ordered from us if stones are to be broken in areas with strong electrical fields. The reason we deliver Class 2 igniters as standard is that the Class 3 igniters require more power, which limits the number of cartridges that can be detonated in series. Further, the battery in the igniter unit becomes exhausted much more rapidly when using Class 3 igniters.