The sleeve fits the 12.9 iPad Pro (2018 model) perfectly. The 11" would obviously fit as well, but with a lot of extra room. There is a flap that closes the sleeve top, but it's only for purposes of using it as a stand. You cannot close the top with a 12.9 iPad inside (no idea if you can close it with an 11 inside).
The sleeve fits the 12.9 iPad Pro (2018 model) perfectly. The 11" would obviously fit as well, but with a lot of extra room. There is a flap that closes the sleeve top, but it's only for purposes of using it as a stand. You cannot close the top with a 12.9 iPad inside (no idea if you can close it with an 11 inside).