Some psa graded cards are encapsulated with their penny sleeve is this a special request one must make?
Is there a picture of this? never heard of penny sleeve in case. However mylar sleeve to prevent movement yes
that’s the sleeve yes! Why are they in some holders but not others
PSA sometimes put them into cases where the card shows a lot of movement inside. I am not sure why some(some japanese new backs, some english and some ancient mews) cases have them but smaller cards like yugioh will definitely have them.