WT-3102S
WT-3102S: a manual setting that radio reception can replace
The setup guide directs the owner to select the time zone and daylight-saving setting before inserting the battery. It allows up to five nights for reception; that is guidance for this model, not a universal waiting period for every atomic clock. A later successful reception replaces its manual time setting.
Use this example for a listed zone when automatic correction is the goal. Do not choose it on the assumption that a manually entered offset will remain untouched. Keep the battery compartment and controls reachable during your initial setup check.
Check before buying: You can set time manually, but a later radio update overrides it.