The invention relates to a refractory body for use in a protection system for the interior wall of a furnace. In the method according to the invention, the germ barrier is generated by means of extrusion directly on the foam support. The first ends of each of the first and second contacts extending in substantially the same direction from a first side of the main body and being adapted to engage the printed circuit board. The second divided face is formed by an upper divided face and a lower divided face of the ball recirculating path so that the upper divided face and the lower divided face intersect with each other when viewed from a flat surface of the nut. The displays may further comprise particles dispersed in a suspending fluid, wherein the particles contain a liquid.