This read-write INTEGER designates which stack unit should be pinned to the top or bottom, per rlPhdStackFixedUnitLocation, of the list shown by the CLI's Show-List command. An admin uses this to keep a familiar, stable ordering in CLI output across reboots or stack changes, so scripts or habitual admins reading show-command output are not confused by shifting unit order. For example, an admin who always wants the master unit listed first sets this object to the master's unit number combined with a top location setting.