Stabila Spirit Level 2 Vial, is a smooth-ribbed box section spirit level, the ribbed profile provides extra strength preventing the profile from bending. This spirit level can be used to check the horizontally of overhead surfaces by turning it and its horizontal vial upside down. You can then measure precisely from underneath.1 vertical vial and 1 horizontal vial. Measurement accuracy: in the normal position 0.029° = 0.5 mm/m. For overhead measurements: 0.043° = 0.75 mm/m. Stabila patent. Vials that are moulded in.Stabila 80AN Level 2 Vial.Length: 1000mm (40 in).