The unifix 1-10 stair is the most popular accessory in the unifix range for good reason! The "stair" Consists of ten joined vertical grooves in which joined rods of unifix cubes (sold separately) are placed to match the values printed at the top of each groove. Cubes placed in the grooves demonstrate each number as a grouping of ones. Ideal for reinforcing and teaching number, ordering, and sequencing. The stair is made of durable plastic for years and years of classroom use, and measures 8.5" X 8.875". Unifix cubes sold separately.