Edward VII wall boxes feature an ornate "ER" (Edward Rex) cypher and the Tudor Crown, a departure from the earlier Victoria Regina (VR) boxes. These boxes, installed between 1901 and 1910, were initially modified from the Victorian patterns but were later designed with the proper Tudor Crown to show the reigning monarch. While many Edward VII wall boxes were installed, they are not as rare as Edward VIII's, which were produced in very small numbers due to his short reign.

Edward VII boxes prominently display the royal cypher "ER," representing "Edward Rex," or King Edward. Unlike the earlier Victorian boxes with the Imperial State Crown, Edward VII designs correctly feature the Tudor Crown. The cypher on Edward VII boxes is described as "exceptionally ornate". Edward VII wall boxes, like other wall boxes of the era, were smaller and designed to be fitted into a wall, as opposed to the freestanding pillar boxes. Originally, these boxes were green but were repainted to the now-familiar "pillar box red" to improve visibility by 1884.