Tubigrip® Pull On Elastic Tubular Support Bandage, 2 3 4 Inch x 1 Yard, 1 Box of 12 Bolster Rolls Wedges Accepted by leading authorities as Style:1 Pair (Left & Right) 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 Acoustic feedback cancellation Bandage moves with you and adjusts to the contours of the body It's stretchable and flexible for easy application around ankles