"This AcuRite Weather Rain Gauge has a variety of rainfall modes in inches or millimeters to keep you alert and in-the-know. This functional rainfall gauge includes Event, 1-Day, or 7-Day settings; 2 user settable totals; history (for each mode); rainfall alarm in increments of .5""; and flood watch alert. Features a self-emptying rain bucket, an easy-to-read LCD screen, low-battery indicator, and clock/calendar. Can be placed on a tabletop or hung on a wall. Display requires 3 AA batteries (not included), and sensor requires 2 AA batteries (not included). RF Range: 100'. Main Unit: 3H x 4.88""W x 2.25""D. Outdoor Sensor: 6""H x 4.75W x 2.88""D. Stronger, 433MHz signal works through walls and from long distances Rainfall modes in inches and millimeters for Event, 1-Day, or 7-Day Measures up to 99.99"" Rainfall alarm in increments of .5"" Flood watch alert Easy-to-read LCD screen Self-emptying rain bucket Clock and calendar Can be placed on a tabletop or hung on a wall"