Gap extrusion is a type of damage to sealing elements. It belongs to the category of damage caused by mechanical stress. In the case of gap extrusion, pressure is the cause of the damage. The sealing element is pressed into the sealing gap, especially with pulsating pressures. This is located between the two surfaces to be sealed. During this gap migration, characteristic peeling occurs where the sealing element touches the edge of the groove. This fully or partially sheared material is also known as an extrusion flag. The loss of material can lead to a reduction in the sealing effect.