Ishihara 38 Plate Chart Book for Color Blindness Ultrasound Units Accessories Comes with Batteries E1 3 Comes with Batteries Specifications: Weight: 99 lbs 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