RT8100 is a fully programmable two channel fridge/freezer alarm thermometer. Insert one probe in the freezer and one in the fridge, set the high and low temperature limits, and the RT8100 alarms when your product is outside your limits so you can quickly remedy the problem. Each channel can be set to alarm at any temperature from -40°F to 158°F. Preset limits are included, but are user programmable. Choose an audible or LED alarm for notification. After 30 minutes in alarm, a duration counter will tell you the elapsed time since the alarm condition began. If the temperature returns to normal while you are away, a caution symbol will remain on the display to prompt you. The counter continues to show elapsed time since the alarm began so you can calculate the time. Min/Max will also indicate the highest and lowest temperatures reached during your monitoring cycle. Each probe includes a suction cup holder with three feet of small gauge cable to attach into place and secure in the closed door. The RT8100 takes two standard AAA batteries and includes a convenient fold out stand and magnetic rear panel clips.