Hummmm!!!! seems like they would have put the crystal internally instead of out in plain site where it easy to get at. Oh well. Thanks for all the information. If you have a rx that is both hi and low band, like the futaba 16 can you legally put any crystal in that you need. For example if one of your tx is low say channel 20 and another rx is high say 42 can you use the same rx just change crystals to match the tx? Whew!! I think that was a long question. Hope no english teachers in the forum.