Day Owl Backpack vs Day Owl Slim - Ultimate Comparison 。Day Owl Slim Pro Backpack in Pale Olive Green. From website: The Slim Pro has every feature of the the Backpack Pro in a slightly lower volume and profile. If you’re below 5’10” and don’t need that extra space, this bag’s for you. It fits a 14in laptop, and the insulated neoprene sleeve fits a 32 oz water bottle (a narrow-necked bottle fits best), but it’ll also fit your smelly workout clothes or a wet umbrella (it was designed for a small bottle of wine). It all comes in materials that don’t get any more sustainable. The Slim Pro has the lowest carbon footprint of any professional backpack in its class. Dimensions: 15.5\"H x 11\"W x 3.5\"D New with tags in original packaging, some surface marks that were there on arrival and are part of the style of the canvas