So I don't know what is the correct size for comic backboard.

I went this weekend to a comic book store. I needed some backboard for my collection. I found a place close to where i work. Not a bad place. I got this funny vibe about this store, like i did not belong in here. I will go back and see if i get the same funny vibe. But back to story, I thought i found the correct backs for the plastics. I was informed by the clerk that i had the wrong size. I don't think it normally would bother me, but it was fact that the genius was so vague about the correct size. That i don't think I was going to get the correct size no matter what size backs, i brought back. After my second trip, he went back and go the correct size for me. Again, I think he could just said the type or brand it would have help. Oh well, i got what i needed despite the aggravation.