This is a portable gas leak detector …please see photos of box for the gases it detects and for where or the type of industries where it would be useful.. eg brewing, sewage, leaking gas bottles…etc. I meant to buy a carbon monoxide tester but bought this in error…we’ve never used it. I’ve removed our address label from the front of the box which is why it looks a bit odd. All the instructions are there. It needs three AAA batteries, not included and comes in a grey drawstring pouch and box.