The device used by the Boston Red Sox in their infamous sign-stealing controversy has been revealed as a Fitbit product, according to a major-league source of Nick Cafardo of the Boston Globe.

Though Fitbits are used as a tracker to measure an individual's steps and levels of fitness activity, many products - specifically Fitbit Surge - can be synced with mobile devices and receive text messages.

A member of the Red Sox training staff was accused of using some form of technology, initially believed to be an Apple Watch, to relay signs from the New York Yankees.

Shortly after, it was revealed that the Yankees filed a complaint to MLB after they mistook Red Sox starter Doug Fister's mouth guard as an earpiece.

In a separate claim, the Red Sox said the Yankees stole their signs using YES Network cameras. Both teams were investigated by the league, which led to an undisclosed fine that will be donated to Hurricane Irma relief efforts in Florida.