These interlocking, beautifully crafted, wooden blocks are completely compatible with existing unit block sets. Their unique design provides for taller towers and easier stacking for young builders, while encouraging new opportunities for problem solving and creativity. Used alone or together they will introduce a new stability to standard block play. Single unit measures 2 1/2" wide x 1 3/8" thick x 5 1/2" long. 32 piece set contains 20 units, 10 double units and 2 quad units. Weight 23 lbs.