The Lux Clock MFG of Waterbury was founded in 1914 by Paul Lux (1868-1947). Its movements (LUX 30-hour guaranteed non-over wind movement) were produced by Lux starting from 1920th. First known advertisement of this chess clock appears in Chess Review in 1933. It is a relatively small clock: it is optically identical to the old Austrian clocks; on the other hand, a vibrillator in the shape of a heart reminds a well-known Jerger 'Olympia Hearts'. Photo: Radio match between Chicago vs. Puerto Rico (1947). Another evidence: Pan-American Chess Congress (Hollywood, 1945).

First official USCF chess clock, perfectly described in the Chess Life magazine (March, 1968). Produced in the 1960th in the USA. Flags are positioned at rear side of the clock, being dropped with a characteristic buzzer sound. Knobs to set the hands are positioned vice versa on the front. Very unusual clock dial: just 10 Minutes with 15 sec increment. Paper clock face, covered by the acrylic glass. More information could be found here. Photo: Tigran Petrosian preparation for the match with Fischer, along with Viktor Korchnoi (left) and Yuri Averbakh (1971).