I purchased it seeing the 16" size in the description and was not sure if this was meant for a 15.4". But, when you receive the package and pull the sleeve out of the box the packaging surrounding the sleeve says 15.4". I almost turned to a friend and gave it to him thinking it just might not fit my new Toshiba. I had an old sleeve that fit like a glove on my old 15.4, but wouldn't fit my new 16". This new sleeve fits the sides snugly, but I have about a one inch gap at the top when the zipper is closed. I use this gap space for just cords and cables. The pocket on the side (on the top if laying flat) are pass-through. You open both sides of the pocket (zippered) and you can put your whole arm through the opening. The pocket has enough room for my power cord, external hdd, and ext wireless mouse. Hope this review helps.