Abstract: An accessory having a first face and a second face connected by a lateral face, the second face having a slot extending to the lateral face, forming on the lateral face a hole the shape defined by the transverse cross-section of the slot. The transverse cross-section has an open contour having a bottom and an opening connected by a first lateral side and a second lateral side, the first lateral side and the second lateral side each having a part approaching from the bottom towards the opening, towards the opposite lateral side. The dimension of the bottom of the contour are constant along a direction defined by a direction extending substantially perpendicular to the transverse cross-section and going from the hole towards an inner part of the accessory. The slot is intended to receive a fastener.