Amazon is opening its first cashier-less grocery store outside of its hometown of Seattle. The new store is opening in Chicago today. Like the other stores before it, it’s open long hours (from 7AM to 8PM), and it doesn’t have any checkout lines.

Amazon has three other Amazon Go stores, all in Seattle, that it launched between 2016 and this year. They’re each the size of a small convenience store, which is far smaller than the average US supermarket. Similar to a 7-Eleven, Amazon Go mainly sells ready-made lunches, drinks, snacks, frozen dinners, and basic groceries.

The stores use hundreds of cameras and sensors to account for what people are buying. People simply need to use their Amazon Go app to enter the store, pick up what they need, and leave. The items get charged to their Amazon account automatically as they’re exiting. The process removes the need for human cashiers and also reduces customer wait time.

Amazon has also named San Francisco as another city where it’s looking to expand. Earlier this year, Recode reported Amazon was considering expanding into six more stores in 2018, including one in Los Angeles and possibly more in Seattle.

In China, where Amazon has little reach, cashier-less stores have already taken off, although the technology is slightly behind. Dozens of venture-backed startups have launched their own convenience stores where customers use products’ RFID tags for a self-checkout, as compared to Amazon’s machine learning and image recognition.

Better yet, tech giants like Tencent, Alibaba, and e-commerce company JD have also tossed their hats in the ring. JD has plans to roll out hundreds of such stores that use facial recognition, QR codes, and RFID tags to successfully skip checkout and curate ads for users. So far, its numbers stand at over 20 stores, including one in Indonesia, its first outside of China. Alibaba opened a pop-up coffee shop last year called Tao Cafe and, more recently, a convenience store within its headquarters in Hangzhou dubbed “Futuremart.” Similar to Amazon’s first few Go stores, Futuremart appears to be aimed mostly at nearby company employees so that Alibaba can fine-tune the technology while ultimately planning for a country-wide expansion.