How to describe to my parents what to get me?

Yeah, It's very possible to find the style number on a shirt. They're normally on the sewn on tags and the price tags. It might be a little annoying to find though. They might be able to ask clerks at the store to search the product number. May just right down a general description with it so they don't have to look at EVERY bag (like it's blue, and large with birds on it, or whatever it is).