A set of panels including a first panel with a first main plane and a second panel with a second main plane is described. The first panel and the second panel are provided with a mechanical locking device for locking of a first edge of the first panel to a second edge of the second panel at a junction plane, wherein the first main plane is essentially perpendicular to the second main plane and the junction plane is extending at an angle to the first main plane and the second main plane between the first main plane and the second main plane.