Backpacks are bags that possess two shoulder straps which allow the wearer to carry the bag on their back. Backpacks are often associated as a student's must have school accessory for carrying books, etc from class to class.
About Checkpoint Friendly:
Checkpoint Friendly refers to bags or laptop cases that can be easily scanned at airport checkpoints. These bags allow laptops to be clearly viewed by security so that travelers will be able to put their carry-on through security without the hassle of removing their computers. To be considered checkpoint friendly, the bags must be approved by the TSA.