My son had been carrying a small Thomas the train backpack when he started kindergarten but it never zipped shut over his proper size binder and lunchbox, and therefore was not very useful.  I ordered the Jansport half pint, hoping it would be large enough but not too large for a 5 yr old - but it was very very small, definitely either for some adventure other than school or for a doll.  I ordered some other one advertized as "good for grade school" but it was sized for a grown up or a teenager.  This one is perfect.  It holds his binder and lunchbox, has a place for his water bottle, and room to spare.  It seems sturdy but we've only had it a day.  At least the size is right.