Leak-proof design: The screw thread finish and aluminium alloy cap ensure a tight fit to prevent any liquid leakage from our essential oil roller bottles.Even when it is turned upside down in your bag, it will not spill. Made of glass with a smooth interior, very easy to clean and reusable | There are a large number of them:10 Pack Purple and Orange Gradient Color Glass Roller Bottles with Stainless Steel Roller Balls.Great quantity for dispensing your diy essential oils to share with your friends or clients | Reusable:Roll on Perfume Bottles and Oil Roller Essential Tools: Our roller bottles have hanging lids for easy access and storage.The gradient colour also blocks UV rays and prevents the liquid in the bottle from evaporating | Size: Each roller bottle is 10ml, the perfect size to hold your essential oils.Compact one, perfect for short trips or business trips, just put it in your carry-on bag and take no space | Complete Set of Essential Oil Tools: Our essential oil roller bottles come with 10 roller balls for essential oils, making them a convenient and complete package for any essential oil enthusiastThe roller balls are made of stainless steel, which is not easy to rust and feel friendly to the skin.