  The charged exotic mesons Z_b(10610) and Z'_b(10650) observed by the Belle
collaboration in 2011 are very close to the B*Bbar and B*B*bar thresholds,
respectively. This suggests their interpretation as shallow hadronic molecules
of B and B* mesons. Using the masses of the Z_b(10610) and Z'_b(10650) as
input, we predict the phase shifts for the scattering of B and B* mesons off
the exotic mesons Z_b(10610) and Z'_b(10650) to leading order in a
non-relativistic effective field theory with contact interactions. Moreover, we
rule out the possibility for universal bound states of three B and B* mesons
arising from the Efimov effect.
