  The $\eta$ production in the $(n,n')$ bottomonium transitions $\Upsilon (n)
\to \Upsilon (n') \eta, $ is studied in the method used before for dipion heavy
quarkonia transitions. The widths $\Gamma_\eta(n,n')$ are calculated without
fitting parameters for $n=2,3,4,5, n'=1$.Resulting $\Gamma_\eta(4,1)$ is found
to be large in agreement with recent data.
