On Wednesday the U.S. cafe chain Panera Bread unveiled Amazon One devices, which let customers scan their palms to pay, for two locations in greater St. Louis. Kumar said the deployment would expand to 10 to 20 Panera cafes in coming months.

A palm swipe would also let Panera pull up restaurant goers‘ rewards accounts and order histories, the companies said.

Kumar declined to state the deal‘s value but described the business model as selling software and devices as a service.