I use a Compur car kit and with the solenoid and I have to turn the bottle on before I can activate the system. I would have much rather had the other to open the bottle. If I leave the bottle on by accident and turn off the solenoid will not turn back on because the nitrous will freeze it shut. I then have to turn the bottle off and undo the line to have the solenoid work free. It was a waste of money in my book. The twist on opener would be a better bet. My intention was to be running around town and be able to turn on and off the bottle with just the push of the button.