Beret Flash Description
On a teal blue shield-shaped embroidered item edged with a 1/8 inch (.32cm) black border, 2 1/4 inches (5.72cm) in height and 1 7/8 inches (4.76cm) in width overall, a black horizontal band at the upper third of the shield surmounted by three yellow vertical lightning flashes.

History
The Beret flash was approved on 11 Jan 1972.

Source: The US Army Institute of Heraldry