I adjusted my Compadre's lower shaft all the way in to the last hole and the total length measured 39" from bottom of coil to back of the arm cuff. About 28" from coil to the hand grip. Have your son stand with his arm at the position he would hold it and see if that will work.
The Compadre has a lot of holes to adjust in fact there really isn't any room to drill more. Plus if you did, I'm not sure if it would void the warranty or not. Hope this helps.
Thank mortarman! I'm not sure if that's what I'll get him but ppl hand told me that would be a good one. He is 7 and loves MD. I let him use my ace350 to play around with. Just a lil heavy for him to swing very long.
The Compadre is an excellent detector for a child. Very light, very simple to operate and what most people who don't own one don't realize is that it is a very powerful machine on small gold! You won't regret getting one. I love mine!