Stabila 96-2 Extra strong double plumb ribbed box section levels are made from an extra strong light metal rectangular profile with gripping ridges and removable end-caps made from two materials. The removable end-caps are also equipped with well-proven patented anti-slip stops. Has 2 vertical vials, 1 horizontal vial, and 2 milled measuring surfaces on levels up to 120cm. Levels over 120cm do not have milled surfaces. Measurement Accuracy: in normal position 0.029° = 0.5 mm/m. Overhead Measurement 0.043° = 0.75mm/m.