Skateboards are usually made from multiple materials such as wood and polymers. Usually, the deck of a board will be made of a supple wood such as maple, but have a polymer covering with a grooved pattern. The polymer covering helps with traction and grip, keeping your child firmly balanced on the board itself. The wheels are usually made of a hard polyurethane and come in a range of sizes.
Skateboard wheels come at a maximum size of 60mm, making the board great for slow and multi-terrain rides. Finally, the bearings of a skateboard or the apparatus that keeps the wheels connected to the board are made of steel or aluminum. If you want a faster board, aluminum is lightweight, so your speed increases. If you want a sturdier board, then steel is the way to go.