[Slydria]

I don't think there's any problem with this idea. Given the wide variety of casting tools already available, a magical bracelet doesn't seem like a stretch at all. Having a second bracelet for the purpose of storing spells is also fine.

I imagine something like this could be reasonably made as either a talented one person job or an adequate two person job. Just really need someone like a metalworker to forge the bracelets and an enchanter or whatnot to give it the ability to function as a casting tool.