2 Pack Carbon Monoxide Detectors,Battery Powered CO Alarm Detector,Carbon Monoxide Alarm with Sensitive CO Sensor,LED Digital Display and Sound Warning,Ideal for Home Kitchen Office

This is the 2-pack of GO detectors.First off: they seem to work exactly as described. Note that, like all modern CO detectors, it takes a little while to register the CO level when it goes up. The higher the level, the faster it registers. If the level is dangerously high, it registers within 3 minutes or less, which has been determined by experts to be fast enough. This should eliminate false alarms, even if you ignore the installation advice in the instructions (which you really should not ignore), which, also, apply to all CO detectors.They come each one in its own plastic bag, both inside one double-layer retail-ish cardboard box. Mine arrived with 2 copies of the fold-out instruction sheet, and 1 set of the mounting hardware: 2 screws with 2 plastic anchors. I suppose they usually come with 2 sets. The detector twists onto its base, after you hang the base on the wall or (if you're careful to get it snug enough) the ceiling. You can use either the included screws (and anchors if necessary) or double-stick tape: it's only 5.5oz with the base and batteries (and less than 4" across). They are bottom-heavy, so you could stand one up temporarily, and it will stay rightside-up, even though it's round.They do not show the CO ppm display on the LED unless the alarm is sounding, either because it's over 30 ppm, or because you held the (only) button to test it. This makes sense, because you don't want to change the batteries too often. In normal operation, the green LED flashes briefly every 30 seconds.If the alarm sounds, you can press the button to silence the alarm, and it will keep flashing the red LED and displaying the CO ppm until it's no longer an issue.If it alerts and you do not press the button (maybe you're not home) and the CO level goes back down, an LED will flash until you (get home and) press the button; when you do that, it will show you how high the ppm count got while you were away.Note that, because they responded less well, the older generation of CO detectors advised putting them in rooms with gas-operated appliances. With the new generation, the recommendation is to NOT put them in the room with gas appliances (stove, water heater, dryer), but in or near bedrooms, to reduce false alarms. (I don't know what they would say if you have the old-fashioned wall-mounted gas heaters in your bedrooms.)They run on 3 AA batteries, not included, per unit. Do not try to use rechargeable batteries. I tried Duracell precharged batteries, topped them up before installing, and they lasted about 24 hours before the Low Battery alert sounded. This makes sense, since it's designed to run on 4.5V, and rechargeables would provide only 3.6V. (I guess maybe I should be impressed it would run at all with them.) I highly recommend Lithium batteries for this, as they will last the longest, they're only a few dollars, and after all, how many of these will you have? And if you use double-stick tape and/or put it on the ceiling, lithium batteries are lighter, as well.

This set of 2 Carbon Monoxide detectors are easy to setup. Both units have a pack piece that detaches with a quarter turn. Once separated, you can use the included screws to mount the base to a wall of ceiling and then reattach the detector to the base. These detectors do NOT come with batteries, but I am ok with this as I would rather use a good name brand battery with these rather than some off-brand that it might have come with otherwise.The test button works when pressed and the audible alarm is VERY loud. (Which you want it to be). I am using this in a room with my furnace and water heater to keep my family aware if there are any future leaks for our safety,To test the unit effectiveness, I did put it up to the exhaust of my car and after about 1 minute it begans to sound the loud audble alarm and continued to sound after it was triggered. I am confident that these units will detect Co2 as they are designed to do. Price-wise, I do think this set is priced just a little lower than what I would find in the store and feel it is well priced.

These carbon monoxide detectors were easy to install and work as expected, judging by the test alarm performed. Their size is decent--neither too bulky nor too small--and the alarm is loud and noticeable. I do not like that they each require three AA batteries to operate. I'm used to detectors that require one 9 volt battery. Hopefully, the batteries will last, but I'll keep monitor.

For the price you get two simple, no frills, carbon monoxide detector.What I really like is the unobtrusive size, as one of them is sitting on my nightstand, not taking up too much space.The set up is easy and intuitive, although a comprehensive instruction sheet is included, including the information about the best placement of the detectors.Please keep in mind, that you will need 3 AAA batteries for each device, which are not included.During the operations he display will be dark , but you will see intermittent blinking. It is perceptible, but does not disturbing during the night. The display is supposed to lit up when the levels of carbon monoxide become dangerous, at which time a pound alarm will sound as well. It will also alert to malfunction and low batteryI have not had it long enough to confirm the long battery life, so time will tell.Overall, I’m very happy with this detector - small, inexpensive and practical.

These are like the basic smoke detector that you put batteries in, stick it on your ceiling and that's it. Except, these won't mount to a ceiling. I was hoping the display would give me the current CO ppm but it only lights up when the alarm is going off and doesn't display anything otherwize. Best I could guess they are supposed to go off if they detect > 30 ppm of COYou are told to test it every week. I think that is a lot to ask. I tested it by running a portable generator running on propane inside my garage with the door closed. I have another CO detector that gives real time measurements. In less than 30 sec the reading was 60 ppm and going up quick. I shut the generator off and opened the garage door, it was surprising to me how long it took the CO to dissipate, 15 min later there were parts of my garage that read 18 ppm with the door still open. Unfortunately these detectors never went off.In the marketing info of this page they show values from 50 ppm to 300 ppm around the house. It is my understanding that an average of 9 - 50 ppm is safe up to 8 hours and 90-100 ppm for no longer than 15 min according to the World Health Organization and OSHA. In the product page info it says at 400 ppm you will get headaches in 1-2 hours. Something isn't right.