In a lap seal, the films are stacked at the edges before sealing with the interior side on the exterior side. The films are welded at the overlap; the film seals flush and cannot be peeled open. The package is closed on the bottom and on top with subsequent cross sealing. The seal seam strength is not particularly high, which is why this process is primarily used for providing packaging that simply protects against contact. Lap seals generally use orientated polypropylene, including as a composite. For more refined packaging, triple bonds are often used. It is important that the film is sealable on both sides.