This thermometer only displays the temp where the probe is, not room and water temp as their misleading claim. The temp alarms (2 not 4 as claimed) are preset to alert you if the temp drops below 75 or above 82 degrees, they claim it has 4 alerts which is not true . 75 degrees is max for my tank so alerts are useless. So be sure you can use it before you buy it. I bought 4 different types of digital thermometers and put all 4 in one tank with the probes side by side and all 4 have a different reading. According to my floating thermometer this one reads 2 degrees hotter.