Wikipedia
Visi-Flash was the trade name used by R. E. Dietz Company for their line of battery powered transistorized barricade warning lights. In 1958, Dietz was the first company to offer battery powered barricade lights. These lights are commonly seen along highway construction zones or other road & highway hazards. Before the development of these lights, oil burning lanterns and "highway torches" which resembled cannonballs were used. Naturally these could pose a fire hazard.
The main body of these lights were manufactured of steel and later high impact plastic. The lenses used were mainly yellow, though examples of red, green and blue exist. Their internal circuits were either 6 or 12 volt DC. 12 volt units used a higher candle power bulb though battery life was about half of the 6 volt models. These lights either blink or stay illuminated(no flashing circuit) depending on model with all models containing an on-off switch. Later models also used a photocell for dusk to dawn operation which, extended battery life. Both design voltages used two 6 volt lantern batteries. Certain models of these warning lights command high collector value. There are no current web sources for further information about these warning lights. Several other companies also produced barricade lights but Dietz Visi-Flash was by far the largest, selling them world wide. The trade name Visi-Flash was later purchased by Riva Plastics Corp in the late 1980s. Riva Plastics Corp is no longer in business.