"Rugged enough for industrial use yet compact and lightweight enough to be carried around with you, these infrared thermometers are extremely easy to use. Just aim, pull the trigger, and read the display. The 3-1\/2-digit backlit display shows temperature readings in °F or °C; low-battery indication; and hold, scan, and max. Display holds for 7 seconds. Underrange and overrange conditions are also indicated on the display.Extra bright laser can be easily seen in bright indoor or outdoor conditions! Advanced models 35639-20, -30, and -40 indicate max, min, dif, avg, emissivity, high alarm, low alarm, probe, log, and recall. Other features include an RTD input, 12 datalogging points, and adjustable emissivity.All thermometers come with a hard carrying case."