I keep the unit next to my dog's bed in the garage near our propane heater. I know propane is supposed to burn clean, but you just don't know if you're not monitoring.

This unit feels durable. It's about the size of a hockey puck. Seems like the frame of the device is made of metal, the face and back look like injection molded plastic. Still, if you were to drop it, the plastic has a good chance of hitting the ground, perhaps breaking.

The CO detector picked up on a cigarette almost instantly, when held near the detector. I trust it works.

The only control is a single button. Don't lose the instructions. I found I only really needed to use the button for power on/off, and bringing the display out of power saving mode were it dims the still visible readings.

The included lanyard is cute, but essentially useless. The hook has a flawed design, and won't even clip onto a belt loop.

The battery seems to last a long time. So far, I'd say I've had it monitoring for about 10 hours and it still shows a full charge. I'll see how it holds up.

The temperature and humidity readings are interesting to know. You don't get those on all the different devices available. It's a nice bonus for me.

The display is bright and very easy to read. It dims after some time, still, it is readable. To turn on the bright display only requires a quick tap of the single button control.

The audible alarm is attention getting and fairly loud.

The magnet is not really strong enough to hold it to smooth metal such as the side of a heater. It will slide right down. Other metal surfaces, it seems to work ok on. Don't fully depend on the magnet to hold it in place 100% of the time.

The first one I received rattled, I exchanged it. The second one does not make noise when you move it around.