This five piece set makes powerful model rocket whistle rocket engines for single and two stage with parachute recovery, missles using nose cone #RNCS and fins #RFS (both re-useable) as well as stick guided fireworks rockets with signal flare, bang or stars. The set uses strong parallel wound kraft casings .625" ID X .825" OD X 3 1/2" long for the engine case and missile airframe using the nose cones and fins mentioned. Comes with illustrated instruction booklet listing formulations for two whistle mixtures, delay mix and red star mix. It doesn't take a rocket scientist to get these right the first time!