This diffuser necklace by #Abooxiu is made of stainless steel so it won't rust or corrode. I love the tree of life open work style on a nice stainless steel chain. Makes a great sweater necklace as it's the perfect length. The essential oil absorbing discs fit right inside and can be changed out to go with all of your outfits, as they come in every color of the rainbow. You can also buy or make these discs once they run out. A drop or two of an essential oil on a disc will last approximately 1-2 days, perhaps more. At only $9.99 this makes a wonderful gift.