Item Type: Arithmetic Board for Blind People Material: ABS Size: Approx. 20.8 x 26cm / 8.2 x 10.2in Characteristics: This product contains a board (16 x 20 grid) and 100pcs dice with contacts. Package List 1 x Arithmetic Board 100 x Dice with Contacts Please allow slight error due to manual measurement. Thanks for your understanding. 1Arithmetic Teaching: There are contacts on the surface of the dice, which is convenient for blind people to touch and perceive, so as to better learn and perform arithmetic. 2Mellow And Safe: Smooth surface and mellow corner, will not hurt the delicate hands of the blind when used, can be used with confidence. 3100pcs Dice: With 100pcs dice with contacts, put the dice with contacts into the grooves board to use, simple operation, facilitate the teaching of arithmetic for the blind. 4Compact And Portable: Light weight and in small size, suitable for different places such as home, schools for the blind, parks, etc. 5Firm ABS Material: Arithmetic board adopts high quality ABS material, safe and eco friendly, stable and firm, sturdy and wear resistant, durable for long term use.