Supco IAQ55 Handheld Indoor Air Quality Monitor, 0 to 2000 ppm, 1 ppm Resolution, +/-75 ppm Accuracy

I'm not sure why this came with such a large plastic case but it seems to work well and I found it easy to set up and calibrate. I can find no faults with this unit.

This same product is offered in diffent colors by other vendors, at vastly different prices. Be aware that with the expensive item you also receive a 120 VAC - 9VDC power supply for this product, and also the very rare RS232 to USB converter. Neither are included with the Supco product, thus the low price.The serial/USB converter cable is rare because the serial socket on the monitor is not the usual 9 pin serial plug or socket, but is a socket like the audio socket on your cell phone or other device. You can certainly find an inexpensive 120 VAC/9VDC wall transformer, and if the output plug is not the 3.5/1.3 mm center positive that you need, it is easy to buy a converter or change the output plug. I suspect the best way to obtain the RS232/USB converter that will work with this monitor is to buy this cable from one of the other providers of this monitor, for $70.00 plus shipping. Fortunately I have no interest in data-logging.The relative humidity calibration can only be done using the 33% and/or 75% salts. If you own a sling psychrometer and thus have a very good idea what the relative humidity is, this does not help.The alarm cannot be turn off. If you have no need for the alarm, all you can do is set the thershhold very high so it will not go off. It comes with the CO2 threshhold set at 1000 PPM. I of course carefully inspected the device, inserted the batteries, turned it on, carefully watched the dial, and as soon as the 30 seconds warmup was done, it started to beep. The co2 was over 1000 PPM because of the proximity to my breath.But I like it and for the money I am very satisfied with this Supco product.

let just start by saying this "supco" is not made by Supco, Even they said so they just put there name on it and another "america" company selling there souls to the Devil. I called them three times to figure out what was going wrong and couldn't get anywhere. I had enough got a return and went to a local plumbing supply house and got a real one.

Very easy to use! I just got my monitor and it is very accurate and fun to use. Im very happy with this purchase.

It's a decent enough product. The relative humidity was way off. Luckily, I have an rh calibration kit from another company's similar unit (same exact monitor, different company name). I used that to calibrate the rh. CO2 and Temp were fine. Hard to beat the price. It was cheaper to buy this unit, then to send a previous unit in for calibration. Go figure.

Quick turn-around and good quality product. Exactly what I wanted; thank you!

Great product, works great!