Btw, some brands of RXs and cystals are interchangeable, some aren't. Futaba, Hitech, and FMA all use the same FM duel conversion Rx crystals, so you can buy by price among those brands. JR uses a cyrstal that will only work in JR gear. I don't know about any others.

(I routinely swap FMA and Hitech cyrstals around when I change channels, and I've seen other guys swap Hitech and Futaba. I don't have any Futaba stuff myself. I personally like Hitech cyrstals because they have a really nice paper label that tells me what channel it is and makes it easer to get in and out of the RX)

I just read the link provided by Jim, that's a great article, should be required reading for anyone past newbie stage. I picked up a couple of things I didn't know, and it had a lot of great explinations for the "whys" of things I did know.