backpack

Google is the answer here just google a review of the backpack, and see if any of them compare it to the other backpack. That is pretty much the only solution unless someone on this forum has used both and can tell you exactly which is unlikely.

The other solution, is to look up the measurements of each bag to see and compare it the 15" MBP. In my opinion this would be the easiest option seeing as most bag manufacturers give the dimensions of the bag.

OR

You could just get a sleeve for the MBP and then put it in the bag and never worry about this again.