If you're looking for something a bit sturdier then I would recommend kollector_protector box protecters. They are 0 .5mm thick and you can really feel the difference between kollector's and others. I started swapping out my Video Game Box protectors for these because they feel more durable and they have a nice snug fit. I've tried the SNES and NES box protectors so far.
The Ebay link is here: https://www.ebay.com/str/kollector-protector?_trksid=p2047675.l2563