Bullet vial is made of quality 316L stainless steel is wonderful for essential oil, a lock of hair, a tiny note, ashes of your loved one, or beach sand. The stainless steel bullet vial is just under 2.0" (49 mm x 9mm), & comes on a stainless steel 3mm rolo chain. Made in Minnesota USA from EW (Earth in Wire), copyrighted & patent pending by Earth in Wire. Take advantage of our introductory price of $29.99. Use for essential oil: The aroma gently diffuses through a tiny hole in the cap of the vial where the chain feeds through; therefore you can enjoy your oil all day without opening the cap. When not in use hang your liquid fill bullet to prevent possible seepage. Fill the oil just BELOW the thread lines. Make sure you screw the bottom on tight. This vial can also be made into a water/airtight or permanently sealed vial. 1st for water/airtight, open the cap and apply a good adhesive, (epoxy, of locitite) on the tiny hole. 2nd to permanently seal your vial, apply a good adhesive to the screw area and your keepsake will be permanently sealed. Note: this high quality stainless steel chain may vary from the picture although it will be of similar quality & size. Your necklace will arrive in a jewelry bag.