ETDRS Standard Illuminator, LED light source technology, providing uniform and highly calibrated illumination across the entire testing surface. Automatically adjusts to incoming power of 100 to 240 VAC. Controlled by infrared wireless remote. Optional Glare lights are available. Generous chart storage in back. Compatible with all existing high contrast (black) ETDRS charts. Measures 24.5"H x 25.5"W x 3.75"D