Review on Enhanced Safety: Sensorcon Industrial CO Carbon Monoxide Monitor - Visual, Audible, and Vibrating Alerts, Waterproof by James Lesley

Nice gadget. Well made, you can tell it's not junk when you pick it up. I use it to check CO levels while driving some of my old cars and also to check CO levels in a garage. It's quite large to carry as a keychain but easily fits in a cup holder. Although we have a carbon monoxide detector upstairs, my wife likes that in the winter when the gas stove and gas water heater are on a lot, she can walk around in the basement and check the carbon monoxide levels.