This is a 2oz PET French Square Bottle and has a 28-410 neck finish. The french square is an elegant and classic bottle. Polyethylene terephthalate (PET) is of the polyester family and has high clarity, good chemical resistance, high impact resistance, and medium rigidity. PET is also light-weight and is used for products containing essential oils. Avoid using PET containers to store products that contain essential oils greater than 5% or fragrance oils greater than 15%. If your oil percentages exceed these respective levels, please consider using glass. These bottles are sold by the case (100 count).