Metal lugs (caps) are also referred to as twist-off. This 38 mm black metal lug closure has a smooth top and smooth side. It includes a plastisol liner which creates an airtight seal when heated and then cooled. These liners are acid resistant thereby they are perfect option for canned food items, sauces, pickles and any other acidic food items. Plastisol lined caps are the perfect option for hot-fill processes. Note: Lug caps must be paired with a container that feature a lug finish. They are not compatible with containers that have a continuous thread finish.