Stainless Steel Roller Ball: The roller ball is made of stainless steel, which is corrosion resistant and well made. The seal is good and prevents any kind of leakage. Essential oil glass bottles are made of corrosion-resistant glass, thick, smooth and shockproof to prevent essential oils from evaporating quickly. Applicable: Pack of 42, 10ml per roller bottle. The perfume rollerball bottle capacity allows you to store synthetic oils, natural oils, essences, perfumes or other liquids for your daily care needs for your eyes, face and body. Double Seal Process: The threaded finish matches the cap and fits snugly to prevent any liquid leakage. You can also use these lovely roller ball bottles to design your essential oil recipes that will help you relax in the salon. Mini Portable: Perfect for travel and conveniently fits in your purse or pocket. The perfect enhancement to your essential oil collection.