Adjustment plates GN 2277.1 are used in combination with bull´s eye spirit levels GN 2277, Type A.

The mounting bore holes offset by 120° allow the bull‘s eye spirit levels and the mounting plate to be aligned in relation to the mounting surface. An alignment ball at the bottom surface of the adjustment plate serves as tilting point. Specific tightening torques of the bolts allow to be achieved, so that the bubble is located inside the marking ring once the horizontal alignment is reached.