The single packaged Crayon rockets come right out of the packaging RTF, requiring only minor assembly to attach the chute and nose cone to the shock cord. I was surprised when I opened the box and saw that the rockets in this kit were not RTF as advertised. The engine mount requires gluing and will need to set and dry overnight, but flying the same day as assembly will require you to use two part epoxy. Also decals are not applied to these kits - minor, yes... but if you start them crooked, they stay crooked. You don't get a second chance to straighten them out. Overall - great kit. The kids love all the colors. They fly a nice good low flight with a B motor, and streak into the sky nicely on a C. Also, keep some plastic cement on hand to repair cracked/broken fins.