m.a3783909wrote a review of Arc'teryx Mantis 26 Daypack - 1587cu in on April 18, 2010
The main compartment fits a 1.5 inch 3-ring binder, a 14" laptop and a medium sized textbook. A 15" would probably fit fine as well. The side pockets fit a tall 1L bottle but it's tight, so I'm not sure about one of the shorter/wider 1L bottles. The top compartment has plenty of room for a calculator, pens/pencils, and all the small stuff. The two front areas are roomy and good for some gym clothes or other things that aren't too rigid. The waist strap doesn't do much, but this pack isn't big enough to warrant them anyway. The shoulder straps are a bit stiff but it's still new so i'm sure they'll break in over time. Overall, this is a great, balanced pack for school as long as you don't need to bring more than a few books. I bought is because of the load balancing which is focused more towards the top of the pack and whether walking or biking, this pack does just fine.