This sleeve is just that, a sleeve for a tablet or notebook. The pocket is 10 X 12 inches but extends another exposed 2 inches. There is a mesh zippered pocket on the outside that is about 8 X 8 inches. On the opposite side is a large strip of Velcro measuring 11.5 X 4 inches. I would have liked to have seen a flap to secure the main pocket for use not inside the Nitecore BP25 backpack, otherwise you have to make sure it is carried upright so the tablet/notebook won't slide out. Since it is made to be used with the Nitecore BP25 backpack, it would most likely work fine in it. (I do not own the Nitecore BP25.) The buttons in the description must be referring to the backpack, because there are two rectangular D rings at the top of the sleeve, no buttons.