This 16-piece set Mini Hollow Blocks are sized to standard unit block construction. Beautifully constructed with birch plywood and solids, and no exposed screws or hardware. Edges are rounded and surfaces are sanded smooth for safety and hours of creative play. Blocks are sealed and fininshed. For indoor use only. Ages 3+. Largest block measures 11"W x 5.5"D x 2.75"H. Smallest block measures 5.5"W x 2.75"D x 1.25"H.