HUNKY DORY Transparent Plastic Roll-On Bottles This roller bottles set is leak-proof designed, so the black lids is maybe a little tight for the bottles. To protect your precious essential oils, please kindly use more strength to screw it on tightly. ABOUT OUR PRODUCT · 100% Leak Proof The tightness of the insert prevents any leakage while the roller ball makes it easy to apply the oil evenly, no more rollers getting stuck or falling out. The screw thread finish roller bottles for oils mouth matched with the cap, which fits tightly and can effectively prevent any leakage. · Premium Quality The Glass Roll-on Bottles are made of corrosion-resistant glass which are thick, smooth and protect essential oil from harmful UV rays to avoid rapid volatilization. · Portable and Convenient 10 ml per bottle. Perfect for travel, and conveniently fitting in your purse. The capacity allows you to store essential oil, essence, perfume or any other liquids meet your needs of daily care for eyes, faces and body.