First and second MR elements are provided with a plurality of element patterns each having a stacked structure. 1%, and amount of MnO2 less than 1300 ppm, an amount of Co more that 55 ppm and it has a selectivity higher than 1. The elongated bonded structures are arranged in different arrangements and reduce the chance of shorting between neighboring bonded structures. 2) and the aggregate particles have 0. The vanes are configured to minimize turbulence and the loss of energy through the corner, and to attenuate transmission of sound generated within the wind tunnel.