the small cabinet uses LEDs to illuminate the panel and offers uniform lighting across the chart face - for high contrast vision testing and contrast charts like 50.028.02, 50.028.03, 50.028.04 and many other models - this small illuminator cabinet is portable and easy to use and provides the ability of testing in many different environments - LED cabinet is great for testing distances ranging from 40 cm to 4 meters - it can be wall mounted or used with a table stand - chart pocket in rear to hold charts when not in use - sold without charts - measure 38x27x3cm and weighs 3.5Kg - input 24V