Did you get it right?
Two modern mailing details slipped into this small-town post office scene.

The Answer
The correct answer is: the modern adhesive shipping label and the plastic bubble padded mailer.
Here is why
- The parcel on the counter has a modern peel-and-stick label with a barcode-style block.
- A gray plastic bubble padded mailer sits under letters near the front of the counter.
Why people miss it
Both items still belong to mailing, so they feel natural at first, but their materials and label style are much newer.
What answer did you get before checking?