Fish Finders

My family does secret santa every year and usually I get one of my girl cousins, well this year I got Uncle Ben, he loves to fish, currently building his new house (he’s a carpenter) doesn’t like high tech gadgets and gizmos bc he wont use them, they’re “too complicated” I have no idea what to get him. I thought of a Garmin Fish Finder GPS but he kayaks so idk if he would take the time to mount it, ans it might be a little too modern for him. Im at a loss you guys, please help me!!
Appropriate please, my whole family will be there.
Oh another thing, it has to be about $100. And I think he has more fishing stuff than Cabela’s, so anything I get him (fishing wise) would be pointless : (