The Large Abacus, model 1-03170-00, is an abacus designed for use by children who are blind or have low vision and fine motor disabilities. It is a 13-rod soroban abacus with large beads that can be used by those who lack fine motor skills. Both frame and beads are made of high impact plastic. DIMENSIONS (LxW): The frame measures 8.25 by 4.5 inches. Beads are approximately 7/15 inch in diameter.