Something strange is going on here because I have a box right in front of me too, and it says sulfate. They must make (or have made) Bronkaid in more than one formulation. Either way, I use Bronkaid for my ECA stack and it works great.
Ephedrine HCl is approximately 82% ephedrine by weight.
Ephedrine sulfate is approximately 77% ephedrine by weight.
25 mg ephedrine HCl = 20.5 mg ephedrine
25 mg ephedrine sulfate = 19.25 mg ephedrine
Duchaine used to say the sulfate is easier to assimilate. I think he was thinking of the size of the HCL crystals when to compared to SO4. Which is not an issue in modern drug manufacturing. For all practical purposes they are identical.