TOPWEL 50pcs 3 Ml Refillable Amber Glass Roller Bottles with Balls and Black Caps (50) Capacity: 3.0 milliliters Size: 16mm x 47 mm (0.63 x 1.85 in.) Roll on Bottles with Balls and Black Caps Perfect for storing perfume oils or other liquids Perfect for applying diluted essential oils and blends directly to the skin.