Use this HABA Kullerbu Windmill 25 - Piece Starter Track Set for indoor play. It's perfect for kids who love building and playing with tracks. There are 25 pieces in the set. Have fun rolling the pieces through the building, around the loop, and through the windmill. Ring the bell and enjoy the musical sound. The set has different heights to add more excitement. It's easy to use with a clever click system that keeps the pieces in place. You can also expand it with other Kullerbu sets and accessories.