Precision-made, straight-grained, kiln dried, hardwood blocks with sanded, beveled edges. The unit block is a standard 1 3/8" x 2 ¾" x 5 ½" size, all others are multiples or divisions of this size. Our sets contain more units and double units for greater play value. Ages 2 yrs. +. GUARANTEE: If any block breaks or splinters, we will replace at no charge.