Last September Amazon introduced a touchless payment system called One that literally reads your palm to authenticate purchases in Amazon’s retail stores. That’s apparently going so well that the company has decided to expand it, at least at its home base in Seattle. Starting today, Amazon One touchless palm-reading tech is coming to the Amazon Go location at Madison & Minor, and will expand to two additional locations “in the coming weeks,” Amazon said.

Amazon said it’s had “great feedback” from customers about the convenience of the One system. It has also touted it as more hygienic than other systems thanks to the touchless functionality. Since a person’s identity can’t be directly linked to their palm-print, it’s apparently more privacy-centric, too. Finally, it eliminates the need for cameras, smartphone and other security measures to check out in the cashier-free Go stores.

Amazon One tech might eventually come to third-party retailers and expand to other Amazon bricks & mortar stores down the road. Right now, it’s available in six physical Go, Books and 4-star locations, including the Madison & Minor Amazon Go store in Seattle’s First Hill neighborhood, starting today (February 1st). It’ll arrive in the coming weeks to another two Go stores at 5th & Marion and Terry & Stewart .