HOLLOW BLOCKS - Now stronger than ever!! Birch and maple construction, all joints reinforced with heavy duty screws. KYDZSafe™ edges are carefully rounded and sanded. The large size encourages group play and cooperative activity. A set consists of six basic parts - Half Unit, Full Unit, Double Unit, Ramp, Short Board, and Long Board. Full Unit measures 11" wide x 11" long x 5" high. KYDZSafe™ edges KYDZTuff™ finish Birch and maple construction Lifetime Warranty Item # Description 2521JC 2522JC Introductory Nursery Set 2512JC Half Unit 4 6 2513JC Full Unit 2 5 2514JC Double Unit 2 4 2516JC Ramp 2 4 2517JC Short Board 2 4 2518JC Long Board - 4 Number of Pieces 12 27 Number of Shapes 5 6