SAO PAULO (Reuters) - Neymar likes them Brazil-green. England's Wayne Rooney, white. Luis Suarez, blue.
Banned from the pitch by Fifa for licensing reasons, the bulky Beats headphones are a favourite for many of the world's top players, making the World Cup a huge unofficial ad for the company acquired by Apple Inc last month.
The colourful high-end headphones created by rapper Dr Dre have become a ubiquitous soccer accessory.
Neymar wore them as he stepped off the bus at the Castelao stadium of Fortaleza for Brazil's last training season on the eve of their match with Mexico on Tuesday. Suarez had them wrapped around his neck as he joked with his Uruguay team mates during a break at a recent practice.
But soccer world governing body Fifa's licensing agreement with rival electronics maker Sony Corp means players have to take them off when they are in World Cup stadiums for official matches and media events.
Marketing experts say that probably only amplifies their appeal. "When fans see World Cup athletes wearing Beats in their downtime, by choice, it has as much impact as seeing them lace their Adidas (boots) or sip a sponsored beverage," said strategist Ellen Petry Leanse. "Maybe more, actually - Beats isn't a sponsor, so the message is more authentic and credible."
Beats Electronics is known for "guerrilla marketing" tactics to bypass licensing barriers.
During the 2012 Olympics in London, for instance, the company sent thousands of free headphones to high-profile athletes, outsmarting official sponsor Panasonic.
A five-minute film featuring Neymar, Suarez, Germany's Mario Goetze, Netherlands' Robin van Persie, Mexico's Javier "Chicharito" Hernandez and other players wearing Beats headphones released days before the World Cup has been seen by 10.6 million people on YouTube. Its name? The Game Before The Game.
Sony this month issued all players participating in the World Cup with a free set of its own headphones, but few players have been spotted with them wrapped around their necks.