Panera Bread is rolling out palm scanners that will link customers’ handprints to their loyalty accounts — a move the company paints as convenient but that privacy advocates have decried.

The biometric-gathering technology, developed by Amazon, will hit stores in the next few months, Panera said on Wednesday. The gadgets will help suggest menu items based on customers’ order histories and allow employees to greet customers by their names and share customers’ available rewards, the company said.

Panera Bread CEO Niren Chaudhary described the move as a “frictionless, personalized, and convenient” evolution of Panera’s loyalty program, which boasts 52 million members.

The fast-casual chain has already installed the scanners at locations in St. Louis, where it is headquartered, and says the scanners will “expand to additional locations in the coming months,” although it’s unclear how many of the chain’s 2,000-plus locations will be affected. Reuters reported that Amazon One technology