  For an infinite dimensional Hopf quasigroup, if the faithful integral exists,
then it is unique up to scalar. Base on the faithful integrals, we construct
the integral dual of a class of infinite dimensional Hopf quasigroups, and show
that the integral dual has a similar structure to Hopf coquasigroup, which is a
regular multiplier Hopf coquasigroup with a faithful integral.
