Agreed. It's so simple and the little patches are cheap. It comes with whites one and thicker red ones. The box says that two reds used together will blow at 150psi and send the rocket up 1000 feet, When we tried it, it got up to 175 and we couldn't pump it anymore... never blew, so we tried 3 white ones, those blew at about 170psi and (i'm guessing) went about 1000 feet. A lot of fun without having to deal with the safety issues of rocket engines.