Levelling sets GN 350.5 are used for levelling, adjusting and linking operations. The spherical washer allows precise installation of two non parallel planes at a required gradient up to ≈ 4°. They comprise a threaded upper sleeve and an internal threaded lower sleeve. The fine thread allows a stepless and precise setting and locking using the C-Spanner DIN 1810. A locking ring serves as a height limiter for the max. height.