Kel-Lite was the first heavy-duty aluminum bodied flashlight, which became popular with law enforcement agencies due to its heavy construction.

According to company founder Donald Keller, a Los Angeles County Deputy Sheriff, he began working on the concept in 1964 as he was tired of the lack of durability of the generically available, cheap metal flashlights of the day; the prototype was largely designed by 1968.

[1] Keller's primary concern was to develop the flashlight as a defensive tool; the illumination provided an ancillary benefit.

The small head Kel-Lite (SKL) was introduced in 1970, and the company also began marketing law enforcement equipment such as speedloaders and traffic wand attachments.

After Keller left in 1972, he continued designing lights for a new company (Pro-Light, 1973), later moving on to Maglite (1979),[1] Brinkmann, and ASP.

The second generation Kel-Lite was designed by Norm Nelson in 1973, featuring a battery charger, adjustable lens, baton lights, and a push button switch.

Surviving Kel-Lites are still in use worldwide, with the final design by Norm Nelson, marketed by Streamlight as the Excalibur, sold into the early 1990s.

Prior to the Kel-Lite, flashlights were relatively fragile and undependable, usually made either of molded plastic or stamped sheet metal.

Salesmen trained by Keller would demonstrate this for public safety customers by pounding large nails into a block of wood, while the light was operating.

The success of the Kel-Lite led to the rise of competition, primarily Maglite and Streamlight, who improved on Keller's basic concept.

Maglite developed an improved switch and a variable-focus system, allowing a single light to be used for a high-intensity flashlight or wide-angle lantern.