As World Cup fever sweeps the globe, millions of fans are donning their favorite team’s national jerseys. And while the United States isn’t competing at the 2018 World Cup, it has two sporting manufacturers who are dressing about 40 percent of the teams playing in this year’s tournament.

Though Adidas has long been the go-to company for team kit in world football (or soccer as it’s known in the U.S.), American manufacturer Nike has been making inroads and World Cup newcomer New Balance also is sponsoring teams in the tournament this year.

Soccer players lined up for photo (© Antonio Calanni/AP Images)
England’s kit is inspired by the colors of the U.K. flag and includes the three lions seal. (© Antonio Calanni/AP Images)

The most anticipated article of fan gear is the team jersey. This year, Nike’s eagle wing-inspired design for Nigeria sparked a craze. Millions of jerseys reportedly sold out within minutes of their appearance online.

Two soccer players competing for ball (© Darko Vojinovic/AP Images)
Nigeria’s eagle-inspired kit (left) draws on the spirit of the country’s alternative name, “Naija,” meaning “the new Nigeria.” (© Darko Vojinovic/AP Images)

Designers take into account national identity and tradition when they create the team kit, which includes the most cutting-edge sportswear technology.

“With Nigeria, we wanted to tap into the attitude of the nation,” said Dan Farron, Nike’s Football Design director. “We built this kit and collection based on the players’ full identities.”

Two soccer players competing for ball (© David Vincent/AP Images)
France’s kit (left) incorporates their tri-colored flag and the Gallic rooster emblem. Australia’s kit (right) is inspired by their 2006 World Cup-qualifier win when fans were asked to “create a sea of gold.”  (© David Vincent/AP Images)

International competitions are an ideal venue for companies to debut new, innovative designs and materials that wick away moisture and improve performance.

Soccer player leaping in air (© Pavel Golovkin/AP Images)
South Korea’s kit features an abstract design drawing from the colors of their national flag, in a pattern inspired by the markings on a tiger. (© Pavel Golovkin/AP Images)

Designers must decide how they will incorporate the desires of the national teams, while also adding fresh new elements. Some countries have specific design choices in mind, such as a specific color like with Brazil’s iconic yellow jerseys.

Soccer player leaping in air in celebration (© Themba Hadebe/AP Images)
Brazil’s kit is representative of their flag. The shade of yellow is called “Samba Gold,” the color Brazil wore in 1970, the first time the World Cup was broadcast in color. (© Themba Hadebe/AP Images)

Others are open to novel ideas. New Balance designed a jersey for first-time World Cup participant Panama that incorporates the Panama City skyline and has a line from the national anthem inside the collar.

“Panama’s qualification for [the World Cup in] Russia was an incredible achievement. We look forward to seeing this kit on the world stage, worn by the players and the passionate supporters who will be following in Russia, back home in Central America, and across the world,” said Kenny McCallum, general manager of New Balance Football.

Soccer players embracing (© Petr David Josek/AP Images)
Croatia’s classic checkerboard motif is emblematic of the coat of arms on the country’s flag. (© Petr David Josek/AP Images)

Ultimately the fans decide what constitutes a successful design, by buying up jerseys to show off their team pride.