2 way radio

Are there any good knock off 2 way radios for helmet/headset on amazon that work? Generally I have been against them as I thought that it would be a distraction and take away the fun with someone in your head telling you what to do lol. My son has asked for me to get one though to try it as he has seen some other kids at the track with them and he has noticed they have all gotten really fast since when he first saw them use it. I don't want to splurge for something I don't fully believe in and don't know how he will react when I am able to talk to him while he is riding. If you have any suggestions links would be appreciated.