The padding is some kind of foam, or sponge. You can squeeze it, every piece of it works independently, so lace make a line in it.
The guard is some kind of plastic. You cannot squeeze it, entire guard works as one piece, so lace has a surface of it.
The lowest models of Vapors line is X.70, and of Supremes One.7 (the thickness of the guard is different though). Lower models have only padding (foam).
The question is -- what is the lowest model of Nexus that comes with guard, not padding.
Please don't quote official Bauer website, it is incorrect for Vapors for sure, so I would not like to rely on it for Nexus.