Our classy long lasting Room Diffusers come in a cut glass bottle with a silver topped cork. The reeds come in either natural, or black ( when available). The bottles are filled with a base oil which we then add our fragrance oils. They last for a long time ( have been told by a customer 18 months ). Turn the reeds upside down every day for two to three days until the oil has diffused into the reeds. These are best if put in a sunny spot.