Visit www.sprigtoys.com "Designed for the active preschool child, our vehicle and character bodies are molded using SprigwoodTM – a durable, child-safe, bio-composite material made from recycled wood and reclaimed plastic." The toys are made from recycled materials and have little generators in them (no batteries). Basically the more you run with the toys, the more they’re charged, the more the toys do (lights light up, toy begins to play music or tell stories). My nephew has the “discover rig†and loves it. The only thing is, you need a decent amount of space to push the rig to really get it going.