Our 16 piece set of Mini Hollow Blocks are sized to standard unit block construction. Beautifully constructed with birch plywood and solids. No exposed screws or hardware. Edges are rounded and surfaces sanded for safety and hours of creative play. Blocks are sealed and finished. For indoor use only. 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. Ages 3+.