They do exactly what they promise. They perfectly embrace the card, protecting it from moisture or anything that could alter it, while at the same time being completely transparent to clearly display the artwork and not blur like others I have tried. It is obviously an inner sleeve, meaning you use it under the regular sleeve that you will put on the cards. I use it for the holos (holographic, changing colors depending on how the light falls on them) that I have, because they are more sensitive to moisture and I have not encountered any problems in the year and a half that I have been using them.