A 20 mL empty glass bottle is a type of container that is specifically designed to hold and dispense skin care products, such as serums, toners, or creams. Glass bottles are a popular choice for skin care products due to their durability, transparency, and resistance to UV light and heat. They are also easily sterilized and can be used multiple times. A 20 mL empty glass bottle is a relatively small size, and may be suitable for travel or for products that are meant to be used sparingly. The capacity of a bottle refers to the amount of product it can hold, and is typically measured in milliliters (mL). A 20 mL bottle can hold approximately 0.68 fluid ounces of product.