Continuous thread closure allows you to thread smoothly and seal tightly every time. This 38-400 white polypropylene (PP) plastic continuous thread closure has a ribbed skirt. This cap includes a pressure-sensitive foam liner PS113. The liner is designed to be used as an inner seal for dry products. These closure types are widely used across Cosmetics and hair products, Craft paints, Adhesives, Food and Pharmaceutical. Note: Pressure sensitive liners provide an extra level of protection in that it actually creates a seal that sticks to the rim of the bottle.