Builder Boards are interlocking wooden blocks that allow kids to build their dreams at large scale. They provide for creative problem-solving and open-ended construction play, both indoors and out! Like all loose parts, Builder Boards can be played with in many different ways. They invite kids to explore and discover what they can build. Each set supports cooperative and social play as kids work together to construct whatever they imagine! Builder Boards have been around for over 20 years and are thoroughly kid tested! We have made sets for preschools and children's museums around the country. This new Preschool Set is just like the original, just a bit smaller and less expensive. The set includes over 100 pieces which can build an entire playhouse, or any number of other creative possibilities. They are sanded perfectly smooth to the touch. The boards are made of super high quality 1/2″ exterior-grade poplar plywood, left raw or finished with a choice of durable and non-toxic finish options: Interior Oil Finish - Penafin Verde Exterior Stain - Rubio Monocoat Hybrid Exterior