the abacus from ancient China; its characteristic is that the counting system used before modern numbers is still used by some businessmen, traders and clerks. It is a good tool for mathematics education.This 17-digit professional abacus is made of high-quality ABS plastic and measures 10.5 x 2.5 x 0.75 inches (26.5 x 6 x 1.5 cm) An abacus that makes math exercises more effective; using an abacus to calculate children's mathematical ability is a good way to teach them to count and calculate intelligence.It can be used as a classic office calculator, a teacher's, an educational tool for children or a gift for abacus collectors. The abacus is very suitable for fast calculations. It is highly recommended to use it in any math abacus course. Dear customer, Thank you for choosing our products. If there is any problem with our products, please through the order information. We will be happy to serve you and solve it for you as soon as possible within 12 hours, thank you Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.