The Walkie-Talkie Wristwatch is a small communications device concealed inside a watch.
Walkie-Talkie Wristwatches were invented in 1936 in Poland. There were less than twenty of the watches made. S.H.I.E.L.D. later made a new version of the technology, having a large model by 1955.
Phil Coulson's Collection
One of the items in the collection that Phil Coulson maintained in his office was a Walkie-Talkie Wristwatch, the first version that was created in Poland in 1936. The watch still worked, but it was destroyed when Coulson jury-rigged it to detonate in order to free himself and Skye when they were trapped in his office by Tobias Ford.
During a time-traveling mission, S.H.I.E.L.D. agents arrived in an alternate 1955. Pascal Vega showed the Walkie-Talkie Wristwatch to Jemma Simmons and Phil Coulson, whom he believed to be Peggy Carter and Gerald Sharpe. Vega later showed it off to visitors of Area 51, noting the large size.
The walkie-talkie wristwatch could be used to communicate over long distances while being disguised as a wristwatch. It could also be manipulated to detonate and open a door if needed.