Apple has announced that it is temporarily discontinuing sales of its Apple Watch Series 9 and Ultra 2 smartwatches in the United States, starting this week. The decision was made as the tech giant is trying to resolve a patent dispute over the blood oxygen measurement function on these devices, according to Reuters.

The move follows an October ruling by the US International Trade Commission (ITC), which found that the Apple Watch infringes on the patent rights of medical technology company Masimo. The ITC decision is currently under review by President Joe Biden until December 25. Expecting that it will be upheld, Apple has decided to proactively comply with a potential ban on watch imports to the US.

If the ban is not vetoed, it will take effect on December 26. Apple plans to suspend sales of the latest Apple Watch on its website starting December 21, and in Apple retail stores after December 24. Models without a blood oxygen sensor, such as the cheaper Apple Watch SE, will not be affected by the patent dispute.

Ryan Wright, program vice president at research firm IDC, commented that the court’s decision, if upheld, will likely affect Apple’s sales in January and February, typically slower sales months in the US. He noted that Apple has sufficient stock of Watch 8 and SE models to cover this period. The biggest concern is whether Apple will be able to continue to use the controversial blood oxygen sensor technology in future devices, or whether it will have to negotiate a settlement or find an alternative solution.

In October, Masimo CEO Joe Keaney expressed his readiness to negotiate with Apple. He emphasized the importance of respecting the ITC’s decision to protect intellectual property rights and maintaining public confidence in the US patent system.

Despite the discontinuation of sales in the United States, the Series 9 and Ultra 2 models will remain available for purchase outside the United States.

Apple has appealed the ITC’s findings and plans to appeal the decision in the Federal Circuit, arguing that it was erroneous. The company’s shares closed 0.9% lower on Monday after the announcement.

Previously, Masimo accused Apple of poaching its employees and using its pulse oximetry technology in the Apple Watch. A jury trial in a federal court in California ended in May with no verdict, and Apple filed a separate patent infringement lawsuit against Masimo in Delaware.

Earlier, the U.S. Patent and Trademark Office rejected Apple’s request to reconsider the validity of patents related to the ITC decision. Meanwhile, according to Bloomberg, Apple engineers are adjusting algorithms in smartwatches to change the way they define and present the pulse oximetry measurement function.

Apple is exploring various legal and technical options in case the ban is upheld. The company has begun preparing its stores for the changes by removing images of the Series 9 and Ultra 2 from promotional materials. A spokeswoman for Apple told Bloomberg that the company is submitting a workaround to the US Customs Service to obtain permission to resume sales.

Masimo believes that Apple needs to modify the hardware to comply with the patent requirements, while Apple itself has not commented on its next steps. The company, however, has stated its commitment to ensuring that Apple Watch is available to customers and is taking all necessary steps to return the devices to store shelves if the ITC’s order is enforced.