A sponsored geofilter for Wendy's jalapeño fresco chicken sandwich drove 42,000 people to visit its stores. Snap

Snap Inc. executives frequently tout Snapchat as the best place for advertisers to win over its youthful, primarily millennial user base. Now the company is letting advertisers track those users based on the stores they visit.

A new tool called Snap to Store will let advertisers track where Snapchat's 158 million daily users go in the real world on an anonymized basis. Marketers will be able to correlate ad campaigns in the app with actual foot traffic.

The tool is available to any advertiser with physical stores in the U.S. that meets an undisclosed minimum spend amount, a Snap spokesperson told Business Insider on Wednesday.

Snapchat’s app relies on a phone’s GPS to determine users’ locations, including which stores they are visiting. Users can opt out of being tracked and turn off the app’s access to their phone’s location altogether.

A select few advertisers, such as Wendy's, 7-Eleven, and Paramount Pictures, have already participated in a closed beta of Snap's new tool. Wendy's, for example, found that 42,000 people visited its restaurants in a seven-day period after seeing a sponsored geofilter for its jalapeño fresco chicken sandwich.

Snap has made a number of moves in recent months to refine its ad offerings as it steps up competition with more established players like Facebook and Google. The company has disclosed that its average user spends 25-30 minutes per day in Snapchat and opens the app 18 times per day.

A 2017 Snapchat-commissioned study by Greenberg Strategy found that 80% of Snapchat users have opened the app at a restaurant and 66% have used it in a shopping mall. Snap has said that the key to growing its business will be further monetizing its highly engaged users in more developed ad markets, like the U.S. and Europe.