Masimo sues Customs and Border Protection over Apple Watch's blood oxygen monitoring feature reinstated

Apple was sued by medical device manufacturer Masimo, which claimed that the blood oxygen wellness feature in the Apple Watch Series 6 infringed its patent for blood oxygen saturation measurement. As a result, Apple was unable to include the blood oxygen monitoring feature on Apple Watches sold in the United States. However, with the release of iOS 18.6.1 and watchOS 11.6.1 on August 14, 2025, Apple released a 'redesigned blood oxygen monitoring feature' for US Apple Watch users, making the blood oxygen monitoring feature available again. Masimo has again sued Apple over this 'redesigned blood oxygen monitoring feature.'

Masimo Sues Customs Over Apple Watch's Restored Oxygen Tool (1)
https://news.bloomberglaw.com/daily-labor-report/masimo-sues-us-customs-over-apple-restoring-watches-oxygen-tool

In June 2021, Apple was sued by Masimo, which prevented it from including the blood oxygen monitoring feature in Apple Watches sold in the US. However, in August 2025, Apple released a 'redesigned blood oxygen monitoring feature,' making the blood oxygen monitoring feature available again to US users. The history of the Apple Watch's blood oxygen monitoring feature is summarized in the article below.

Apple Watch's blood oxygen monitoring feature is back in watchOS 11.6.1 - GIGAZINE

Apple will release a 'redesigned blood oxygen monitoring feature' because Customs and Border Protection (CBP) unilaterally reversed its previous decision on August 1, 2025.

However, on Wednesday, August 20, 2025, Masimo filed a complaint in the U.S. District Court for the District of Columbia alleging that CBP's decision exceeded its authority. Masimo is suing under the Administrative Procedure Act and the Due Process Clause of the Fifth Amendment to the U.S. Constitution.

CBP policy states that such decisions typically require hearing both sides, but Masimo said it was unaware of CBP's reversal of its decision until Apple released its 'redesigned blood oxygen monitoring feature.'

In his lawsuit, Masimo points out that around the same time that the CBP overturned its ruling on August 1, Apple announced that it would invest $600 billion in the United States.

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Masimo has filed a petition for a preliminary injunction and preliminary restraining order to prevent CBP from enforcing the August 1 ruling, which would have allowed Masimo to import its products into the U.S. on the condition that the blood oxygen monitoring function be disabled.

Masimo argues that CBP's unilateral decision is an 'extraordinary deviation' from its duties and violates its own policy of 'requiring adversarial proceedings absent exceptional circumstances.'