ESV1500, using advanced patented technology, self-calibrates illumination on chart surface for both photopic (85 cdm2) and mesopic (3 cdm2) light-level testing. LED lights provides uniform and highly calibrated illumination across entire testing surface. Controlled by infrared wireless remote. Optional floor stand and glare lights are also available. 4.5 Lb. ESV1200's LED lights provide uniform illumination across entire testing surface. Both units automatically adjust to incoming power of 100 to 240 V AC and are compatible with all 9" x 14" Good-Lite charts but are not provided with this unit and must be ordered separately. Can be powered by an optional battery pack. 9-1/4"W x 15"H x 3-1/4"D (38.1 cm x 23.5 cm x 8.3 cm).