Large,12-40 inch characters visible from max.2100 feet,90 degree viewability simple 3-button control Energy efficient:uses up to 1/40 the power of incandescents No maintenance or lamp replacements Available in red or amber -40 degree to 85 degree working environment Angle viewing:90 degree Display options:display time in 12 hour format.Display temperature in celsius Special feature: EXternal temperature probe Power:120V AC 10% -50HZ,220V AC 10% -50HZ