To many, myself included, there are no more definitive partnerships between an automaker and a watch company than Bentley’s longstanding collaboration with Breitling. Having worked together for 19 years, though, the final timepiece commissioned by the British luxury carmaker has left the watchmaker’s factory.

The watch, a Breitling Premier B21 Chronograph Tourbillon 42 Bentley Limited Edition, was part of a highly limited run of just 25 units. It cost $52,000 and was described as a reinterpretation of the original Breitling Premier wristwatches of the 1940s.

With a 42 mm case made of 18k red gold, it has distinctive rectangular chronograph pushers, a gold brown alligator strap, and a green face as an homage to the British Racing Green that Bentleys have long sported.

Read More: New Bentley Breitling Tourbillon Watch Is Limited To 25 Pieces And Costs $52,000

“We’re proud of what we have accomplished together and after 19 years, Breitling and Bentley are embarking on their own new journeys,” said Georges Kern, Breitling CEO. “I know that Bentley will continue to define excellence in the automotive industry. The final Bentley Tourbillon leaving our factory represents a moment of positive reflection for us all.”

The companies’ first collaboration came at a defining moment in Bentley’s history. In 2002, the automaker approached Breitling to design the onboard clock for the Continental GT. It made its first appearance on the market in 2003 and came at a time when the British automaker was launching its offensive. In fact, Bentley has made three times as many vehicles since the Continental GT arrived than it had in the 90 years before then.

In the 19 years that followed, Breitling has worked with Bentley to create watches celebrating the brand’s GT3 race cars, its victory at the 24 Hours of Le Mans, the “Blower” Bentley, and more.

“The long-standing collaboration between Bentley and Breitling demonstrated that when two like-minded brands work together authentically, the performance of both is enhanced,” said Bentley’s CEO Adrian Hallmark. “We look back on the past two decades with great affection and send our warmest best wishes to the Breitling team for the future.”