Sustee Aquameter Soil Moisture Meter Small Size Extend the life of your beloved houseplants with the SUSTEE moisture reader sensor. SUSTEE is designed and made in Japan and is the perfect addition to various houseplants. It has a slim, minimalist aesthetic that doesn't take away from the beauty of the plants. It works with almost any plant that grows in soil. When using the stick, the white color indicates that the plant needs watering, and the blue color indicates that it has enough water. The core insert that determines if watering is needed can also be manually replaced. It is recommended to replace the refillable core of your SUSTEE after 6-9 months of use. SUSTEE has won multiple international awards including the Reddot Design Award, Germany Design for Asia Award, and the Japan Good Designs Award. How to Use: Sustee size S is best for pots with a diameter of 6-9cm. Just stick the aquameter into the soil and water your plant generously, in 5-30 minutes the indicator on the top will change color from white to blue. When the indicator turns completely white again that means it`s time to water your plant. When you notice your Sustee doesn`t change color after watering your favorite houseplant, it`s time for a change. Our pens are maid to last, but of course to keep them working their best you need to make sure to refill. Just pull Sustee from the pot Remove the top screw cap by turning it counterclockwise and look inside to make sure none of the used core material is left behind. Make sure you replace all components in a single operation: Inner core, blue sheet and straw. It is rare but possible that the straw is left behind inside the main unit. If this happens, simply remove it with a pair of tweezers. Replace used inner core with a new one.