The only issue I have ever heard about is if you mix crystals. Meaning a Futaba radio Hitec reciever and a Futaba crystal in the reciever. There are talks that the multiplexers in the crystal has a communication issue with reciever. Of couse there are a lot of people who have never had an issue I just offer the advise and say for a 12$ crystal why take the chance. Hitec reciever use a hitec crystal Futaba reciver use a Futaba crystal. And either Futaba or Hitec radios are compatable. I use a Hitec reciever and a Futaba Radio.