I have the NX model. It has an adjustable slipper clutch for adjusting the amount of torque applied to the valve. You have to hold the open switch for 2-3 seconds to fully open and close the bottle. Don't know much about the other types.

RVM Short Shifter RVM Intake Pipe Full Kenwood System NX Neons "If you can read this, thank a teacher; If you are reading this in english, thank a soldier"