How is a ZB-guardian/ Z-guard column in GC different from a guard column in LC?

A ZB-guardian/ Z-guard column in GC acts a s a barrier that prevents nonvolatile analytes from entering into the analytical column. It also helps in peak focusing phenomena. So it acts both as a  guard column and a retention gap column in GC depending on the type of injection. However a security guard in HPLC acts guard to the analytical column and has no effect on peak focusing.