  Following the discovery of blue large-amplitude pulsators (BLAPs) by the OGLE
survey, additional hot, high-amplitude pulsating stars have been discovered by
the Zwicky Transient Facility. It has been proposed that all of these objects
are low-mass pre-white dwarfs and that their pulsations are driven by the
opacity of iron-group elements. With this expanded population of pulsating
objects, it was decided to compute a sequence of post-common-envelope stellar
models using the MESA stellar evolution code and to examine the pulsation
properties of low-mass pre-white dwarfs using non-adiabatic analysis with the
GYRE stellar oscillation code. By including the effects of atomic diffusion and
radiative levitation, it is shown that a large region of instability exists
from effective temperatures of 30,000 K up to temperatures of at least 50,000 K
and at a wide range of surface gravities. This encompasses both groups of
pulsator observed so far, and confirms that the driving mechanism is through
iron group element opacity. We make some conservative estimates about the range
of periods, masses, temperatures and gravities in which further such pulsators
might be observed.
