I’ve had some rudimentary devices to measure pollutants for about the last five years, but they didn’t give me much helpful information. I recently purchased to Laser Eggs + and the difference is remarkable. When we turn on our gas range in the kitchen, the Laser Egg + immediately shows an increase in VOCs. I mean immediately! It gives me a lot of confidence that I now know exactly how my inside air is behaving, and it helps me modify my routines to keep my family safer. These devices are well honed measurement machines. I could not be happier with them. Nicholas J.