1/4 oz natural-colored PP plastic thick wall jar with 33-400 neck finish. Thick wall jars are 1-piece jars with thick walls. More material goes into making these thick wall jars, giving them heft and a raise in elegance. This jar is made of polypropylene (PP). PP is light-weight, durable, flexible, and highly resistant to fatigue and heat. It has a high shatter-resistance rating. This jar is typically used for lotion, cream, serum, gel, putty, clay, hair products, skin products, cleanser, and other personal care products. This jar has a 33-400 neck finish, and will fit closures with the same finish. The first number is the diameter of the container's opening (in mm). The second number refers to the thread/style/depth of the closure's skirt.