Not sure about the clasp, but the outfit screams Aderyn. Practical to a T.
THOR BØGELUND (1890-1959) FLYVER - FEST / TIVOLI. 1916. Promoting a flying festival held by Tivoli, featuring the first night flights in Denmark; as planes flew over Tivoli, they were lit by huge searchlights. The event also marked the first showing of an aerially photographed movie" (Danish Posters np). It is interesting to note that this event took place in the middle of World War I, which could likely only happen as Denmark was not a participant.
Tivoli by Bogelund, Thor
Tivoli by Bogelund, Thor (1920) | Shop original vintage posters online: www.internationalposter.com