The 8-Digit Talking Calculator, model 6638, is a voice output calculator designed for use by individuals who are blind or have low vision. The calculator features an extra-large liquid crystal display (LCD), an audio result only key, a repeat key, and automatic power shutoff. POWER: Uses 2 AA batteries (not included). DIMENSIONS (HxW): 5 x 6.875 inches. WARRANTY: 90 days.