I'm not sure which ones these are as I have purchased three different kinds one of them by mistake. At first I was purchasing just plain top-loading sheet protectors but inadvertently picked up some that were side-loading. They work OK but are not as easy to use as the top-loading. Then I found the acid-free protectors and I especially like them as I have a lot of photos to protect too. I use them for my family history work and I intend to keep that up for a long long time so I'll probably be back for more.