Seam Gap is the distance between the can and end at the top of the double seam.
Seam gap is an important internal measurement of the seam and it requires a computerized double seam inspection system in order to properly measure. In some cases, Seam gap can cause metal pickup, which can give the product a metallic taste. In extreme cases it can lead to leaks. When cans with High Seam Gap are stacked, they can cause leaks due to the movement of the cans against each other. This is why Seam Gap should be as low as possible.