By 1966 "NY/LA" appeared on drawing title blocks, denoting their last expansion, the opening of a branch sales/engineering office in Los Angeles under George Howard.

[16] After 1980, the company's business began to decline, and by the mid-1980s they had moved to a smaller plant at 5 Aerial Way, Syosset, Long Island, New York.

By 1992 the firm was in Chapter 11,[25] and a stockbroker, Richard Davisson, took complete ownership and control, replacing John Kliegl II with Al Vitale.

"[28][29] Indeed, it may be inferred that the use of "Electric" in the company's name was intended to distinguish its products from the illuminating gas or acetylene fueled lime light equipment they would replace.

Many of what became common devices, such as the stage "shoe" or thrust plug and the disappearing footlight were patented by the Kliegls, and many others were developed into the forms still familiar today[30][31] Initially they continued the Myerhofer business as "contractors and manufacturers", as noted in their Catalog G of 1913.

[32] In 1903 they furnished and installed the complete stage lighting system for the Metropolitan Opera Company's new home on West 37th Street (John was at the time an electrician for the Met).

Kliegl Brothers' Catalog E states that "plugs and receptacles are in accordance with Underwriter's requirements and pass city inspections"[29]page 10.

From 1950 to his death, Herbert Kliegl was a member of the National Fire Protection Association (NFPA) code making panel No.

[36][37][29] From about 1908, motion picture studios were using the company's floor-stand arc lamps, which allowed for point-source lighting, including some of the first low-light effects; the shadow produced by the two pairs of carbon rods can be seen in some early films.

[33][29] Pages devoted to Kliegl products in the 1928/29 catalogs of retailers such as Holzmueller on the west coast and wholesalers like Marle in Stamford, Connecticut, showed that their sales now extended well beyond their own factory.

[32] The condensed catalog of 1929 for the first time lists a broader range of "Mazda" (incandescent lamps) than arc spots.

[32] Catalog 40 of 1936 introduced a full line of architectural downlights (individual architectural products had been made for some time), the autotransformer dimmer (originally dubbed the "Transtat", the catalog was overstamped, changing the trade name to "Autrastat"), motor operated dimmers, Fresnel lens spots, etc.

Six artists sat before the tall 50th Street windows on the third floor hand painting the tiny images which would be magnified many times when in use.

Resistance plates and variable brush autotransformers were largely purchased from Ward Leonard; magnetic amplifiers from General Electric.

The first of those control boards were purchased for the MGM Grand Hotel, in Las Vegas, followed shortly thereafter for the San Francisco Opera, and other major venues.

It was moderately successful, primarily because sales were limited to QFile's high costs for such equipment, a single desk selling for upwards of $100,000.

The conceptualizer, and design engineer for the board was Gordon Pearlman, who left EDI shortly thereafter, and was hired by Kliegl in late 1975 or early 1976.

In mid-1976, Pearlman, along with his longtime partner and colleague, Steve Carlson, designed and built the first of many successful, so-called moderately-priced computer consoles for Kliegl, called the Performance.

Another one-off, was developed for ABC-TV, Hollywood, when they requested a console capable of combining the control of multiple channels, and it became the Performancea SofPatch.

By the late 70's, or perhaps 1980, Kliegl brought out the Performer, at the time the only portable computer console, and it found success at every level of the market.

The K96 became a critical product, because its main competitor at time, Strand Electric was dominating the market with its own compact dimmer, which had begun deliveries a few years earlier.

"Klieglight", however, reappears on pages 42–45 of Catalog 40 of 1936 as the name of their new line of ellipsoidal reflector incandescent spotlights, and this usage continued as long as the company was in existence.