What I find so neat about this tool is that it tells you the starting temperature initially. Begin by scanning your area and then the light beam changes color from green to either red or blue. Red, if the temperature went up or blue if the temperature went down. The selector on the unit lets you select the range variance of temperature by either 1, 5, or 10 degrees variances. I mean, even a kid could use it!
Unlike other similar temperature reading devices, this one allows you to have a wider area by placing the TLD100 further away or smaller more accurate by placing the tool closer; great to find the smaller leaks.