Metal Ball Glass Roller Bottle for Essential Oils, Perfumes, Lip Balms, and Aromatherapy Oils, 5ml to 7ml Capacity (12) Practical 5ml -7ml (Max Capacity) Clear Glass Roller Bottles with Metal Balls and Black Caps Durable and Easy to Use Roll Ons NOTE: Only use these Metal Ball Rollers with pure uncut oils. Do Not use Metal Ball Rollers with diluted or carrier oils, particularly fractionated coconut oils. This is a high lubricant oil that will force your metal ball to pop out. For these type of oils you should use plastic ball roller bottles. Use with your 100% Pure Essential and Grade-A Perfume Oils Refillable and Reusable Roll On Bottles