Google has reaffirmed that a sleep breathing quality feature is on its way to the Fitbit Air, the screenless fitness tracker, though it has not said exactly when. The feature has been available on Pixel Watch models since last month, leaving Fitbit Air owners waiting for it.

The feature belongs to a group of tools Google announced under the Your Health Guardian banner. The suite covers blood pressure trends, insulin resistance trends and sleep breathing quality. It is designed for Google's fitness trackers, a lineup that includes the Pixel Watch series, the Fitbit Air and the newly announced Fitbit Edge.

Since the announcement, the Fitbit Air has lacked one of those capabilities: sleep breathing quality. Google addressed the gap in a statement to Android Authority, once again saying the Fitbit Air would receive the feature soon. This time, the company's comments were aimed more directly at the missing function.

Google appears to have anticipated the situation. When it first unveiled the Your Health Guardian features, its press release said sleep breathing quality and other features in the suite would arrive on the Fitbit Air "later this year." That wording was meant to keep Fitbit Air users from expecting everything immediately. The release did not, however, specify that only two of the three features would be available on the device at launch.

Neither the new statement nor the original press release provides a detailed timeline for the arrival of sleep breathing quality trends on the Fitbit Air. The only commitments so far are that it is coming "soon" and that it falls within the "later this year" window Google gave at the outset.

Meanwhile, owners of the Pixel Watch 3, Pixel Watch 4 and Pixel Watch 5 can already use the Health Guardian features on their devices, including sleep breathing quality, insulin trends and blood pressure trends.

For Fitbit Air users, that means a longer wait for the full set of tools. With the year drawing toward its close, Google's earlier "later this year" promise puts the feature's expected arrival in the coming weeks, though the company has not confirmed that.