  We discuss theoretical predictions for ZAHB models constructed either by
including or neglecting the He extra-mixing effect recently suggested by
Sweigart (1997). The comparison in the $log T_e -log g$ plane suggests that
within current observational uncertainties canonical hot HB models based on new
input physics agree with empirical data in Galactic globular clusters and in
the field. We also briefly discuss the impact of the new class of variable
stars EC14026 on constraining the parameters of blue HB stars and their
distribution along the tail.
