The figure of merit is the voltage*model that the device
withstands. Some newer standards even require that it
withstand multiple strikes. There are "Class" bins that
group ESD susceptibility; if you're a manufacturing dude
you may simply want to know that the assembly floor's
ESD threat level is lower than the lowest "Class" part to
be handled, not each one's specific HBM rating.
And of course any / all of this could have been yours
for the Googling, while you were waiting for answers
to be served.