What's New in the BackTpack 4?

Hip-loading belt is an integral part of the bag, not an optional extra. This belt is for taking the weight of the bag off of your spine and shoulders if/when you need to do so for comfort or because of injury.
Locking system for hip width. It allows adjustment for narrower or wider hips, and holds the weight of the bags when leaning forward as in bicycling.
Narrower back panel creates a contour of shoulder straps for greater comfort, sizing, and stability on shoulders.
Streamlined design with angled zipper outer side-pockets.
Replaced velcro with magnets or snaps.
Moved water bottle holder to exterior.
New colors.
Headphone/tube port on each side.
Inside loops to secure hydration bladders. Also, zipper pocket size has been increased to 10 inches x 7.5 inches to accommodate iPads and 45 rpm records for you vinyl collectors. NOTE: with the increased adjustability of this model it can be more easily twisted than the simpler models when initially donning and doffing. With care, this is not a problem.https://www.backtpack.com/product-info/fit-use-instructions/