After opening its first cashierless “Amazon Go” store in Seattle this year, Amazon is planning on more locations, this time opening in Chicago and San Francisco.

First reported by The Seattle Times and confirmed by Amazon, although the company did not give a timeline of when it will open the new stores.

To shop at Amazon Go stores, customers simply scan their smartphone app when they enter, shop as normal and then simply walk out. Amazon’s technology keeps track of what buyers pick out and charges them after they leave.

Amazon’s Amazon Go test store opened in Seattle in January.