Apple has introduced sales restrictions for the iPhone Duo in the U.S. market, permitting each customer to buy a maximum of two units in a single transaction. This policy is now clearly indicated on Apple's official website and within the Apple Store app, ensuring that orders cannot be processed if the specified purchase limit is exceeded. (In English, we typically use "introduced" instead of "imposed" to convey the initiation of a new policy in a more neutral tone. Also, "in a single transaction" is a more natural way to express the idea of one purchase event.)
