Ishihara 38 Plate Chart Book for Color Blindness A P P Pumps Pads Access * Warranty: 2 Years 82 Select Ear:Right Ear * Warranty: 2 Years 82 x 34 x 7 5v handles * It averages 120 minutes of on time between charging * It has the smallest diameter of any 3 Accepted by leading authorities as a simple and accurate method for discovering congenital color blindness and red green blindness each in two forms complete and incomplete * Includes four special plates for tests to determine the kind and degree of defect in color vision * Makes use of the peculiarity that in red green blindness blue and yellow appear remarkably bright compared with red and green * Color plates encased in specially designed album type books for ease of handling * Detailed instructions included