Kids enjoy hours of creative play with these time-honored classroom favorite unit blocks. Crafted from hardwood, which is stronger than Oak, each block is finely sanded smooth to insure it will be splinter-free. All edges are beveled and corners are safely rounded. The roof boards are 1/4" hardboard. These classically designed blocks are based on the precise unit size of 2 3/4" W x 1 3/8" T x 5 1/2" L.