extendable spirit level with stable 3-chamber aluminum rectangular profile and fixed spacers for bridging unevenness on construction elements, additional attachable spacers (height: 4.2 cm) for precise measurements even over battening, extremely long measuring surface thanks to unique telescopic system, strong clamping eccentrics for permanent measuring accuracy, reach-through openings for a safeprofile with reinforcing ribs for high stability, continuous web over horizontal level additionally stabilizes the profile, plastic end caps protect the profile from impacts, strong clamping eccentrics for long-lasting measurementtion, telescopic rod with cmin scale, STABILA installation technology ensures long-term precision, measuring accuracy in normal position (closed) ± 0.5 mmm, in folding position (closed) ± 0.75 mmm, particularly suitable in timber construction and for carpentry work for aligning and adjusting large construction elements, in reinforced concrete construction for setting up prefabricated construction elements.