EZ-Launch Bottle Rocket Launcher w/o air pressure guage The EZ-Launch bottle rocket launcher has an internal spring loaded release mechanism. that allows the user to lock the 2 liter bottle in place during the fill up phase and release the bottle with a quick pull on a nylon cord. Will handle up to 100 psi. of air pressure Suitable for children 5 years and older. Adult supervision required at all times. You can use a bicycle pump or air compressor to pressurize the bottle.