with our diffuser kit you get both the diffuser and oil refill.
oil refill will fill difusser completely 2 times with some left over.
Fill vessel but leave at least 1 inch from top to be free from fragrance. Once fragrance is in and the top is screwed on tip the vessel upside down to allow the wood to be able to absorb the fragrance. You might need to tip vessel over time if smell becomes faint to keep fragrance dispersing in the air.