We present a high precision Monte Carlo study of the spectrum of the Z
(2) gauge theory in three dimensions in the confining phase. Using sta
te of the art Monte Carlo techniques we are able to accurately determi
ne up to three masses in a single channel. We compare our results with
the SU(2) spectrum and with the prediction of the Isgur-Paton model.
Our data strongly support the conjecture that the glueball spectrum is
described by some type of flux tube model. We also compare the spectr
um with some recent results for the correlation length in the 3d spin
Ising model. This analysis sheds light on some nontrivial features of
the duality transformation.