Set of panels with a mechanical locking device

A set comprising a first panel, a second panel and a mechanical locking device for locking the first panel to the second panel, wherein:

• the first panel comprises a first edge surface and a first panel surface;
• the second panel comprises a second edge surface and a second panel surface;
• the first edge surface is facing the second panel surface in a locked position of the first and the second panel;
• the mechanical locking device comprises an edge groove at the second edge surface, a flexible tongue positioned in the edge groove, a rod-shaped element at the first edge surface and an insertion groove at the second panel surface extending from the second panel surface to the edge groove;
• the rod-shaped element is configured to be inserted into the insertion groove and the rod-shaped element comprises a recess;
• the flexible tongue is configured to cooperate with the recess for a locking of the first panel to the second panel in a first direction which is perpendicular to the second panel surface;
• an inner part of the edge groove has a first height and an outer part of the edge groove has a second height that is larger than the first height;
• the rod shaped element is connected to the first edge surface at a first end and comprises a rod surface positioned between the recess and a second end of the rod-shaped element;
• and
• a difference between the second height of the outer part of the edge groove and the first height of the inner part of the edge groove is equal to or larger than a length of the rod surface between the recess and the second end of the rod-shaped element or equal to or larger than a distance from an outer tip of the flexible tongue and a surface of the flexible tongue which cooperate with a surface of the inner part of the edge groove.