An electrical device like this requires a reverse leakage current of 100nA @ 19V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 24V.
GDZ24B-HG3-08 Features
reverse leakage current of 100nA @ 19V 100nA @ 19V is the maximum voltage (Tol)
GDZ24B-HG3-08 Applications
There are a lot of Vishay Semiconductor Diodes Division GDZ24B-HG3-08 applications of zener single diodes.