A set including a first panel, a second panel and a mechanical locking device for locking the first panel to the second panel, wherein the first panel includes a first edge surface and a first panel surface, the second panel includes 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 includes 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 includes a recess.