I'm allergic to the metal on the back of watchs >:[ I think there might be two types, stainless steal, then the kind im alergic too. So far I'm not allergic to stainless LOL. Thats it I think. I'll probably end up like my mom whos allergic to EVERYTHING. I sware she's pretty close to everything..Things like garlic, penicillin, latex, animal dander etc etc etc