Pocket Chair Seat Covers

Do any of you use seat covers with pockets in them on your student's chairs? I bought some from Really Good Stuff 5 years ago, and need to replace them for next year. I was happy with them overall, except that they got stretched out and folders/papers would fall out all the time.  I have seen some that look like they have elastic in them which might make them less stretchy.  Just curious and would love your feedback!