I buy this unit because the specification say he have a powerful and it be perfect for teacher but the device be not even recognize by the laptop , the backlight be terrible in the light of day . the screen size be extremely small and do not match the description give by the seller . definitely do not recommend this product to anyone . the quality be terrible . in addition , I purchase this product from Costa Rica , and now I regret the money spend on this device to bring up my country . this be my first purchase from Amazon disappoint I . people please ... do not buy this unit because they will throw away they money .