Apple is only allowing customers in the United States to buy a maximum of two iPhone Duos. Trying to buy more than two on the website or in the Apple Store app brings up this notice: “A maximum of 2 iPhone Duo can be purchased per customer. Please adjust the total quantity of iPhone Duo in your order before checking out.”

MacRumors reported the limit on Monday , but said it couldn’t confirm whether the cap was in place when pre-orders for the foldable opened on October 16. Some Reddit users said they had been able to buy four units, while others said they were held to two from the start.

The cap isn’t only a U.S. rule. Engadget tried adding more than two units on Apple’s online stores in Japan, Spain and the United Kingdom as well as the U.S., and got the same warning each time, whatever configuration it picked. Apple had clear two-per-customer restrictions listed in China, Singapore and Hong Kong, but the U.S. site doesn’t mention the limit until a third Duo goes into the cart.…