A few days ago, Masimo sued U.S. Customs over its decision to let Apple resume selling the Apple Watch in the United States with the blood oxygen feature enabled. Now, the government agency has responded with a motion to dismiss the lawsuit. Here are the details.
A quick recap
When Apple released the Blood Oxygen feature on the Apple Watch, medical device maker Masimo sued over alleged patent infringement.
Over the years, the lawsuit dragged on and came to a head with an import ban in December 2023, which prohibited Apple from selling Apple Watch models with the Blood Oxygen feature in the U.S.
Since then, after halting sales for a few days, Apple had been selling the Apple Watch Series 9 and Apple Watch Ultra 2 without the Blood Oxygen feature, although it didn’t remove the hardware. Instead, the feature was disabled via software.
Last month, Apple announced that it would resume selling the fully-enabled Apple Watch in the US, with a “redesigned Blood Oxygen feature” that calculates the Blood Oxygen on the iPhone, rather than on the Watch.
That’s when Masimo sued US Customs and Border Protection (CBP), claiming that the agency overstepped its authority and violated due process when it allowed Apple to restore the feature.
From Masimo’s filing:
“It has now come to light that CBP thereafter reversed itself without any meaningful justification, without any material change in circumstances, and without any notice to Masimo, let alone an opportunity for Masimo to be heard. CBP changed its position on Apple’s watch-plus-iPhone redesign through an ex parte proceeding. Specifically, on August 1, 2025, CBP issued an 3 ex parte ruling permitting Apple to import devices that, when used with iPhones already in the United States, perform the same functionality that the ITC found to infringe Masimo’s patents. Masimo only discovered this ruling on Thursday, August 14, 2025, when Apple publicly announced it would be reintroducing the pulse oximetry functionality through a software update.”
US Customs responds
As reported by Bloomberg Law, the CPB filed a motion to dismiss Masimo’s lawsuit, arguing that “Congress precluded district-court review of challenges to Customs’ implementation of the Commission’s exclusion orders,” in a previous case.
In other words, the CBP is saying that the federal district court has no jurisdiction to hear Masimo’s challenge. It is basing this argument on past cases, particularly the Thunder Basin Coal Co. v. Reich lawsuit, which held that when Congress sets up a specific review process, challenges have to go through that process first, rather than straight to a federal district court.
The CBP argues that Masimo must take its objections to the International Trade Commission in an ancillary proceeding and argue that Apple’s workaround still doesn’t clear the exclusion order. Only after that, the CBP says, can Masimo appeal to the Federal Circuit rather than trying to bypass that process with a district court lawsuit.
From the filing:
In short, Masimo can make all the same admissibility arguments it seeks to raise here about Customs’ ruling when arguing to the Commission (and, if necessary, the Federal Circuit) that the Commission’s limited exclusion order should cover the redesigned smartwatches. (…) It even remains free to seek reconsideration of the August 2025 ruling directly from Customs. (…) But it cannot circumvent Congress’ prescribed path for its challenges—proceeding first to the Commission, then to the Federal Circuit.”
The filing ends with the CBP’s call to dismiss the lawsuit, based on “lack of subject-matter jurisdiction.”
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