You and a friend can build & rebuild these dinosaur kits over & over. You decide if you want to build the Tyrannosaurus Rex, Velociraptor, Stegosaurus or the Triceratops. Mix & match is also an option to build your own dinosaur creation. This set comes with a battery operated screwdriver with 2 different tip. Simply install 2 AAA battery and let the building begin. A manual screwdriver is also included so you can build with a friend. Each of the dinosaurs has moving parts which you can articulate. Wheels are built into the bottoms of their feet to allow the dinosaurs to roll along. Package includes: 4 dinosaur kits, screws, battery operated screwdriver with 2 tips, manual screwdriver & instructions. Requires 2 AAA batteries (Not Included). Ages 3 and up.