It is a 12.5" frame with 26" wheels. Your son wants a Camelback? Wait until he wants the clipless pedals, shoes, and the jerseys. He is already hitting me up for Disk brakes! I told him no disk brakes until he starts doing ALL the trails at Alafia, plus he owes SWAMP 20 hrs of trail work. I also have a 5 year old just getting started.
He likes to ride Boyette and Alafia only the intermediate trails. Now that he is on the 26, that will be changing.