I just went to duralite's site and checked for availability. The boxes are $55-8 a piece, need 4 minimum, not counting the wires for my corsair. This set up does save you from buying sbus servos, so the cost is about a wash. I bought the SRS because of the gear sequencer and the igyro all integrated. It is a complex little device! It will be many beers to get it all figured out. Putting it in a 1/3 scale plane first as a testbed before I put it in something more expensive.