Usually, screw plugs (with or without under-head seal) or expander solutions are used for sealing holes. In contrast to screw plugs, expanders cannot be removed without being destroyed. In addition, these sealing elements close off the hole, but require complex preparation of the bore hole. For example, drilling, countersinking, thread cutting, milling of the head contact surface and cleaning the thread when using screw plugs is very costly and time-consuming.