BLUE LED: Normal Transmission. The LED light will occasionally flash blue, indicating it is still transmitting correctly and that no water has been detected.
RED LED: Water detected. The LED light will flash red twice every 5 seconds until dry.
PURPLE LED: Battery is low
Specifications:
Water Detection: 0.7874 when flat, 6.25mm when vertical
Ambient Temperature Range: -40°C to 60°C
Up to 121 meters in open air
Power requirements: 2 "AA" Alkaline batteries (not included)