Fragrance wicks up via the cotton string into the ceramic cactus and continuously diffuse scent to your room.
It will takes 2-3 days for the diffuser solution to be fully absorbed by the cactus. (Depending on space size, environment, and temperature, the strength of the scent may vary.)
Note: After the cactus gypsum is used for a particular scent, it is advisable to use it for the same scent and not to change scent. You can consider to purchase the refills.