Snap-N-Save Sliding Transfer Bench w/Cut Out Swivel Seat Table Paper-Accesories Accepted by leading authorities as Ships From:FL, USA

Snap N Save Sliding Transfer Bench w Cut Out Swivel Seat Table Paper Accesories Accepted by leading authorities as Ships From:FL, USA 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 Adjustable Flow Regulator Easy to turn knob conveniently placed directly below gauge for easy use and control Knob has safety lock feature which will not allow the knob to be twisted off