Last week, when Apple announced the release of a “redesigned Blood Oxygen feature” to the Apple Watch, many figured Masimo (who had been suing Apple over patents related to the feature), would look for a way to fight back. Today, the company did just that and filed a new lawsuit. But this time, it’s against the US Customs and Border Protection. Here’s why.
A bit of background
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. Rather, the feature was disabled via software.
Last Thursday, Apple announced a “redesigned Blood Oxygen feature,” which calculates the Blood Oxygen on the iPhone, rather than on the Watch.
So Masimo is suing again?
Yes. Masimo filed a new complaint in the US District Court for the District of Columbia on Wednesday.
The company says US Customs and Border Protection (CBP) overstepped its authority and violated due process when it reversed its earlier decision on August 1 and allowed Apple to restore the feature. Moreover, Masimo says it found out about the decision when Apple publicly announced the return of the feature:
“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.”
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