Yes there are two RX 18's. The one with the fm crystals gave pretty decent control, and is upgradable as it had a digital input point from the separate receiver. The 2.4 ghz has an internal receiver and does not allow for this option. I have little experience with the 2.4 ghz board, but have been told it does not give very good control. On a pure control aspect it is not as good as it's predecessor, but you get the convenience of 2.4 ghz technology and better range.