First, I want to say that the piston system isn’t for all rockets. Cardboard rockets and dual deploy rockets I would rather not use the piston system. Cardboard doesn’t clean up well, alcohol soaks right into it. However, quantum tube and fiberglass are a breeze to clean BP residue after a deployment. I reiterate, the piston system doesn’t lend itself to dual deploy rockets where the electronics are placed in the coupler; you can’t run your ejection charge past the piston, though, you can easily use the piston system in the payload section to deploy the main chute.