You'll think it's wood until you pick it up. No splinters, firm but not heavy and no sharp wooden corners to worry about. (i.e. 2 squares =1 rectangle).Details:Package dimensions: 7 3/4" x 7 3/4" x 7" , 20x20x18 cm. Set Includes: 30 block pieces, 1 3/8" (3.5 cm) thick, assorted unit block shapes and sizes. WARNING: Choking hazard. Small parts. Not for children under 3 years.