While the M15 and BD5 have been distributed fifteen years apart, the Vandoren CL5 Masters B flat Clarinet Mouthpiece might as well moderate between the earlier and later counterparts, and that moderation also applies to the CL4 and CL6 Masters B flat Clarinet Mouthpieces

Either way, one might even go so far as to collecting the M15, CL5, and BD5 B flat Clarinet Mouthpieces or the CL4, CL5, and CL6 Masters B flat Clarinet Mouthpieces, and the results are always the same.