With this model, you always have your hands free when aligning and adjusting components on metallic surfaces. The 81 SM is equipped with a ferrite magnet system that ensures good adhesion. This model has a die-cast aluminium profile with a bevelled shape that makes it one of Stabila's most robust spirit levels. The vials and milled measuring surface are precisely aligned with each other in the production process and then permanently bonded together to ensure maximum measuring accuracy. As a result, the 81 SM has an exceptionally long service life in construction site use.