Does anyone know what the inner sleeve material is? I looks like maybe it is mylar - which is something I have been wishing graders would do for a long time over the regular cheap plastic they use. It would be even better if it was sealed to protect against off-gassing from the other plastics in the holders, but even if it isn't sealed, it will be a good start.
(Yes I checked their site and no I didn't find specifics:
https://www.cgccards.com/card-grading/holder-label/)