Oversized hollow blocks for giant creations! This 16-piece set is constructed of birch plywood and solids. Edges are rounded and surfaces are sanded smooth for safety and hours of creative play. Blocks are sealed and finished inside and out. For indoor use only. Ages 3+ .Largest block measures: 15.5"W x 8"D x 4"H. Smallest block measures: 4"W x 8"D x 4"H