We have Science Project Experiment Catapult Kit S.P.E.C.K. with Product Detail Can be configured as a Trebuchet, Class-1 and Class-3 lever catapults No glue required. Parts are held together with rubber bands for rapid reconfiguration. Configurations include cupped arm vs. spoon, wheels and no wheels, a variety of arm ratios and power options. All parts, rubber bands, wooden projectiles and 18 page instructions and experiment guide are included. Designed and manufactured in the USA for better quality, better performance! . The "Science Project Experiment Catapult Kit S.P.E.C.K." is best product for you. We recommended Science Project Experiment Catapult Kit S.P.E.C.K.