We purchased this backpack in black for one of our 7-year-old twins going into second grade. We got the small size because she is petite. The backpack is sturdy and high quality, especially for the price. There are three pockets, and the small size DOES NOT include the tiny front pocket as pictured, but she won't need it (the large size does have the small front pocket). It holds quite a bit. I fit a 1.5" binder, large workbook, thin spiral-bound notebook, and a couple small notebooks in the big pocket, a lunch bag in the middle pocket, and a few thin items in the front pocket. We could probably squeeze a lightweight sweater in, too. Each side mesh pocket will hold a bottle, such as standard bottled water or a Nalgene Grip-N-Gulp.
Note: We also ordered a pink and grey/silver from another seller in the large size, so I have included pictures of the large (pink/grey) and small (black) side-by-side for comparison.
We've included a picture of our daughter wearing it. She is 45" tall, 40 lbs. Our other twin, who is 46" and 43 lbs, will be wearing the large size but honestly, the large and small are so similar that either size would comfortably work for either girl.