The publication of RTCA DO 1601 and EN 61000-4-212 modifies the status of the mode stirred reverberation chamber. Once experimental, today they are industrial and recognized. To design a mode stirred chamber, it should take into account several criteria which influence the performances. The dimensions of the reverberation chamber and the size of the mode stirred influence the statistic uniformity and the frequency bandwidth. Nevertheless shielded enclosures with identical dimensions are able to generate different fields in function of the way they are manufactured. To reach high field, it is necessary to use low surface shielding technology, to obtain sufficient shielding effectiveness and to use the correct materials.