Beret Flash Description
A shield-shaped embroidered device with semicircular base edged with a 1/8 inch (.32cm) yellow border, the overall dimensions 1 7/8 inches (4.76cm) in width and 2 1/4 inches (5.72cm) in height, divided equally into three stripes, gray, white and black, and bearing three yellow diagonal lightning flashes, upper left to lower right.

History
The beret flash was approved on 8 Dec 1986.

Source: The US Army Institute of Heraldry