A magnetostrictive application probe is disclosed wherein the probe includes a preassembled sensor element mounted as an application housing installation as an installable unit. At least a part of the immersion nozzle is formed of a refractory having a desulfurizing ability. The expansion output terminal of the first router module is connected to the expansion input terminal of the second router module and the expansion output terminal of the second router module is connected to the expansion input terminal of the first router module.