12 line Flash Bold
Monotype released Flash, the first typeface designed by Edwin W. Shaar, in 1939. Flash Bold was released a year later. Many of the Flash Bold capitals are quite similar in design to those in Balloon Extra Bold, but where Balloon is a caps only typeface Flash has a lowercase alphabet.
The metal Flash that I have access to is cast on an upright body. The wood Flash (and Balloon, and Brush) are cut on an angled body and require angled furniture (shown in the upper photograph) to square up the lines.