The running world is awaiting a decision by governing body World Athletics over what to do about Nike's Vaporfly shoe, a sneaker that has played a starring role in two of the biggest distance-running achievements last year.
A sub two-hour marathon by Eliud Kipchoge and a record-breaking run by Brigid Kosgei.
Their stunning performances have sparked heated debate over whether their shoes gave them an unfair advantage.
And now, a group at World Athletics is examining what to do about the high-tech sneakers.
Among the options facing the organization is to impose a wholesale ban on the shoes or take more limited measures to deal with their carbon plate and foam sole technology.
Independent studies have concluded that the shoes improve metabolic efficiency by 4%, though that does not necessarily mean a runner will be 4% faster.
All Nike says on its website that the shoe, which will run you $250, has a "built-in secret weapon."
But despite all the controversy, analysts tell Reuters the publicity could actually boost sales, especially among amateur runners looking for more spring in their step, since they wouldn't be affected by any ban.