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 for 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 recommend 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. The small size is meant for pot sizes 2, 2.5 and 3. Set of four. Color: green.