A teardown of the iPhone 18 Pro Max reveals it uses a Qualcomm Snapdragon SDX80M 5G modem instead of Apple's advertised C2 modem, but only in the US market. Apple's specification pages confirm the C2 is listed for the iPhone 18 Pro but omitted for the Pro Max in the US, while other markets show the C2 in both models. The discrepancy likely stems from Apple's 2023 agreement with Qualcomm.