backpack options for 4 and 5 year olds.

I'm looking at a Osprey Jet 12 or 18 for the boys. I need something to use for them to carry their sleeping bag and compartment for water bag and a hose support. I think the waist strap is a must as well. They've done 3 long hikes (for them) and managed a standard pack with a youth sleeping bag and a few small items. My 5 almost 6 year old used a large day bag but adult version and it just did tighten down around the waist an shoulder. The bag is much heavier than the Osprey 18

I think I bought my kids a Jet 12. It's pretty small, but should be able to fit a kids down sleeping bag. I usually carry their sleeping bag. I have them carry backpacking pillows, a stuffed animal and a few small toys. No matter how little I put in there bags they have always been the limiting factor on our trips, so I try to get as much weight into and strapped onto the outside of my bag. I try to find the lightest things that let them feel like they are contributing.

yeah after looking at the jet 12 I think i'll option for the jet 18. they have kelty youth sleeping bags but they're synthetic and currently I don't have a compression bag just the stuff sack. The jet 12 also doesn't appear to have a waist belt. My 5 yr old did carry his kelty bag in a large 4lb backpack (appx weight) along with the food bag we used for the trip. I really want something he can grow into and maybe work his way into carrying maybe a liter of water.

The jet 12 does have a waist belt, but I doubt you would get a synthetic bag into it.

Okay thanks. I'm going to get compression sack for their kelty's synthetics. My youngest carried a standard school LLBean book back and got his bag in it with just the stuff sack. According to what you say i'll assume the jet 12 is smaller than a standard bookbag and i'll be assuming the jet 18 is closer to the standard size.

I appreciate the help.

My only other idea was to buy a smaller camelback hydration pack (since they are smaller in size) and attach their sleeping bags to that externally.