The word vapor is ubiquitous within Nike. Vapor products live in apparel. They live in footwear, from soccer cleats to running. But Vapor has held a special place in tennis, ever since the launch of Air Zoom Vapor Speed in 2004. Roger Federer helped make the line the king of the sport. With Federer wearing the line for more than a decade, he helped propel it forward throughout the sport. More major tournaments have been won in a Vapor silhouette than any other tennis shoe.

Now that the word vapor runs across multiple lines in Nike tennis, the two most recent Nike tennis launches highlight the history of the silhouette, both in the Nike Air Zoom Vapor 11 and the Air Zoom Vapor Pro 2, even if they don't have a wealth of direct ties to their predecessors.

The Vapor 11 extends the silhouette that began in 2004, adding an iteration that follows the Vapor 10 (styled as the Vapor X), originally launched in 2018.

Nike says the new Vapor 11 comes more connected to the court than before and stays focused on speed components. "The Vapor 11's design is lower to the court than any of our previous iterations," the company says, "giving you incredible lightweight court feel for bursts of quick movements and explosive cuts."

From a technology standpoint, the Zoom Air unit lives in the forefoot as Nike engineers shifted the most responsive cushioning to the front of the shoe since tennis players spend more time on their toes—from serves to quick changes of direction.

The molded sidewall returns and a full-length foot frame on the outside of the shoe was designed to help with stabilization during cutting. To reduce weight, Nike shaved off rubber in low-wear areas and the breathable mesh upper is meant to improve movement. Nike says the herringbone outsole mixes grip with the ability to slide.

Priced at $160, the Vapor 11 becomes the new pinnacle option in the Nike tennis lineup.

While Nike released the Vapor 11, they extended additional components of the Vapor silhouettes by coinciding the 11's launch with the new Nike Air Zoom Vapor Pro 2, a $120 shoe that mimics much of the technology of the Vapor 11.

The Vapor Pro 2 is also designed with a low-to-the-ground aim and includes Zoom Air cushioning in the forefoot. The shoe features reinforced mesh, a foot frame on the outside and a "stretchy internal sleeve."

While Nike positions the Vapor 11 as a more high-performance model than the Vapor Pro 2, the Australian Open showed that Nike players were often mixed between the two shoes while others haven't yet parted with previous models.

The last five years of Nike tennis footwear has offered a revolving door of designs, with some silhouettes making a one-time appearance and other offerings mimicking the technology of shoes already in the lineup. Seven of the 10 tennis shoes currently on sale in Nike's men's tennis category have "Vapor" in the name and eight of the 10 feature "Zoom."