Good Combination: 1pc green soil moisture meter and 1pc black soil moisture meter in one set, lightweight and enough to meet your needs, help you testing soil humidity easily and quickly, so that you can know when to water your plants accordingly How to Use: Just insert the probe tip into soil to the plant root level for several minutes, you can get the test result from the indicator pointer immediately. No Battery needed. Please wipe the soil moisture probe with a cloth after each use Gentle to Roots: Designed with single probe design, the moisture meter for house plants can keep roots intact and do not dig up to much soil after test, help your plants grow healthy, taking good care of your plants Easy to Read: With the large dial and ten scales with different colors, red means dry, green means moist and blue means wet. Plug and read, responds quickly and provides easily readout Indoor & Outdoor Use - With a 7" soil probe sensor, the soil hygrometer is suitable for garden, yard, farm, lawn plants, house plants, large potted plants etc. Please Do Not use it to test water and other liquid, and avoid very hard soil and stones