The smell of these is extremely strong and offensive. Don't waste your money. Junk, just pure junk. Very disappointed. Better to spent a little more and get damp rid.

The rack and pinion and gears look super fun as kids get older and maybe want to play.

A great intro to engineering / stem for a very fair price. Low temp glue gun to the rescue. The 2aa battery holders have a built in lever switch so one doesn't need to add the included toggle switch which is nice.

Two areas where i would like improvement is a parts list and maybe a description of typical use and morecollars, wheels and axles.

The motor is not strong enough to propel it across any surface. The only useful project you might make from this is a personal cooling fan. These toggle switches are not durable and are cheaply made.