Perfume Studio 10ml Amber Glass Roller Bottles with Aluminum Silver Cap and Stainless Steel Metal Ball Applicator (10, Metal Ball) Perfume Studio Set of True Amber Glass Roller Bottles with a Stainless Steel Metal Ball Applicator - 10 PCS, 10 ml / .33 Oz Specially Designed For Body and Essential Oils IMPORTANT - PLEASE READ!: Don't use metal ball rollers with fractionated coconut oils or similar high lubricant carrier oils. Only use the metal ball rollers with pure undiluted oils and blends with no carrier oils. These type oils makes the metal ball too slick forcing it to pop out. Instead, we recommend using the Glass Ball Rollers. Dark Amber Glass Shield Protects Oils Against UV Light Stainless Steel Metal and Glass Balls are Impenetrable and Less Susceptible to Toxin Contamination, and will give you the smoothest application on your skin.