Spirit level

The spirit level has a bottom wall (28) comprising an outer surface (26) in form of a measurement surface. A bubble body is arranged in a profile body (13), where bubble is optically detected over an opening passing-through a head wall (32). The profile body is asymmetrically formed at a lateral surface along length of the profile body with respect to a vertical axis (18). A side surface (14) has a concave curve in a longitudinal direction of the profile body. A functional element e.g. light and/or battery, is arranged in an interior chamber (70).