I found more info here:
https://www.calibre11.com/history-of-heuer-i-foundation-1920s/
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1880S
On his travels abroad, Heuer had seen that there was also a lot of sales potential in sports timing and this set the seed for what would become the foundation of the company for the century to come.
In 1882, stopwatches appeared in the Heuer portfolio for the first time and soon became the backbone of the company, although trading in precious stones still continued.
The relationship with Fritz Lambelet became strained after a failed proposal to Heuer’s sister and the company in that form was dissolved in 1885, again becoming Ed. Heuer & Cie.
As an interesting historical footnote, the Heuer Lambelet mark would appear again in the 1990s- see below. Having been allowed to lapse by Heuer, it, along with a number of other old watch trademarks were acquired by a Texan marketing company and used to add legitimacy and a sense of history to various brands of watches, largely sourced from the Far East. The Heuer Lambelet and L.B. Audemars brands were eventually dropped as probably too close in name to existing brands, but the practice continued with other lapsed trademarks.

[6]
We sometimes see questions asked about these watches and how they fit in with Heuer’s history. Sad to say, the only relationship is that brand name that Heuer itself last used in 1885.
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