  Magnetic B-type stars are often host to Centrifugal Magnetospheres (CMs).
Here we describe the results of a population study encompassing the full sample
of known magnetic early B-type stars, focusing on those with detectable CMs. We
present revised rotational and magnetic parameters for some stars, clarifying
their positions on the rotation-confinement diagram, and? find that plasma
densities within their CMs are much lower than those predicted by centrifugal
breakout.
