No more guess work for watering your potted plants with the Thirsty Light. This innovative device will alert you when your plants need water by a subtle blinking light. The 9-1/2" corrosion resistant brass probe continually monitors the moisture levels every second. The speed of this green light increases as the soil gets drier, with 5 levels of intensity. No blink indicates there is enough moisture, a slow single blink indicates the soil is starting to get dry, a medium blink indicates the soil is dry, a fast blink shows soil is very dry and a double blink with a pause, indicates soil is completely dry. Operated by a 1.5 v battery, it will even indicate with a triple blink when your battery needs replacing. Ideal for both indoor and outdoor potted plants.