Hewitt Pyrometer, 250° Sweep, 0°F/1600°F (010-213-3R-1) - Black Background, White Characters, Red Pointer, & Red Illumination A pyrometer measures and displays extremely high temperatures, such as those found in your engine's manifold pre-turbo or near the exhaust pipe flange. This 2" diameter pyrometer features a 250° dial sweep, and will indicate a temperature range of 0°F to 1600°F. Red illumination.