These plans are step-by-step (with pictures) to build a cheap but quality water rocket launcher with a complete parts list. Launcher will enable you to propel 1, 2 or 3 soda pop (PET) bottles over 250 ft. into the sky using only water and compressed air from a bicycle pump, a foot pump for a car, or an air compressor. The fuel (water and air) is essentially free and readily available allowing countless launches without additional expense. Launcher supports air pressures as low as 20 PSI up to 120 PSI. You will be amazed how high only 40 PSI will propel a bottle with fins attached to it. After pumping up the bottles to the PSI of your choice (up to 3 bottles can be pressurized simultaneously to the same pressure), you control when the launch occurs by pulling on the string to release the triggers from a safe distance and out of the splash zone. 2 Control valves allow each bottle to be launched independently of the others so you do not have to worry about a premature launch impacting other bottles. Launcher supports 1L, 1.5L and 2 liter plastic (PET) bottles. Great item for people of all ages for fun, science projects, school classes, parties and may well draw a crowd where it is used. Made in the USA from durable non-corrosive Schedule 40 PVC pipe.