Glass bottles are a fantastic choice for holding samples and product, yet without a cap, what good are they? You need the right closure to keep your product inside. These white polypropylene screw caps come with an F217 foam liner, which has a low density foam core between two solid layers of low density polyethylene. They provide chemical resistance and moisture tolerance, and they are a great choice when you ned a general purpose liner to seal household products, liquor, pharmaceuticals, food or other products. Some linerless options are available, and bottles are sold separately.