Thanks guys for the suggestions. My boys are 10 and they started karting late last year but we only average 1-2 weekends a month of running. I certainly understand the part about distracting them while driving. It’s just that when we do the “pit talk” they understand the feedback I give them, but they often forget it when back on the track. I’ve only used radios once with them a few months ago (their instructor had one) and it seemed to work in terms of telling them precisely when to turn in or jump on the gas out of a corner.
But I hear you. If I get one, I will go cheap as I don’t see it as a long term solution. I expect them to learn their lines and technique eventually and thus not rely on a radio going forward.