ZOOB BuilderZ S.T.E.M. Challenge gives you the tools you need to design and build creations to solve challenges, such as hitting targets and making balls bounce. Dream up ingenious solutions for each test. Learn and apply science, technology, engineering and math (S.T.E.M.) principles. Comes with 175 classic ZOOB pieces, plus wheels with axles and rubber tires, a high-bounce ball 24 rubber bands, 2 foam play pads, string, 26 ZOOB challenges plus 9 Bonus challenges, 5 instruction guides to build 40 creations. ZOOB is not like any other building set - the pieces include gears, axles and joints that snap, click, and pop together! With rotating, spinning and extendable parts you can actually design a toy to play with, instead of just building something to look at. Create monsters - or vehicles - or monsters that turn into vehicles! The possibilities are as endless as your imagination! Recommended for children 6 years of age and older.