Root,
I think that Harbor Freight detector is identical to the Radio Shack detector. I'm sure they are all made by the same company, just labled differently depending on who is selling it. Kind of like the way some of the lower-end Bounty Hunters are.
That kid looks like he's about to find a gold ring in the chips and rub it in someone's face! Haha, that's great that he's starting early. Keep getting out there with him and don't let him become one of those video gaming drones like most of these kids these days who refuse to "head toward the light!" of the outdoors. Looks like you're off to an excellent start!
Joe