4 oz black double walled PP jar with 70-400 neck finish. Double walled jars are unique because of its two-layer construction. Built as a jar within a jar, these jars help protetc. against the many perils that can harm your product. A smooth and elegant finish, pair with a dome cap for a €œcompleted€ look, these jars are popular in the cosmetic industries for creams, powder based products and other personal care products. The material polypropylene (PP) has a high resistance to shattering, durable, flexible and light weight. As always, remember to test your product with this specific packaging to ensure compatibility.