ST. LOUIS — Amazon is testing its palm-scanning payment technology at two St. Louis Bread Company locations. Swiping your palm over the device brings up rewards information, account history, and allows customers to pay. Amazon expects to expand the technology to 10 or 20 more stores over the next few months.

The payment system is coming to St. Louis Bread Company locations on Clayton Road in Town and Country and on St. Charles Rock Road in Bridgeton. It is already in Whole Foods, Amazon Go stores, and some sports venues. Amazon is testing the cashier-less technology at more than 200 stores outside the company, according to Reuters.

How does it work? Customers need to link their Panera loyalty accounts to Amazon One. Then enable identification and payments. The scanners are located near the cash registers. One swipe and you’re done.

Adding the payment technology to Panera locations would mean a massive increase in scale for the company. Panera is known as a leader in restaurant technology. There are over 2,000 locations that could eventually see the contactless system in stores.