Assembly tools GN 355.1 serve to adjust leveling elements GN 355 / GN 355.2. They are used in connection with a T-wrench or a hexagonal angle socket spanner. To ease leveling, the top end of the assembly tool has an external hexagon head which is used for turning the leveling screw with a ring spanner, ideally with a ratchet function.

For adjustment, first use the assembly tool to turn the levelling screw of the leveling element into the desired position and at the same time tighten the screw to secure the leveling element. To ensure that the setting found does not change, the assembly tool may be used to counterhold.