You can no longer buy the newest Apple Watches from Apple's online store

• Apple preemptively removed its Series 9 and Ultra 2 smart watches from its online store ahead of an expected sales ban.
• The move comes after a ruling against Apple in a patent dispute over blood oxygen tracking.

Thinking about buying the latest Apple Watch for Christmas? It might be too late.

Apple just removed its Series 9 and Ultra 2 smart watches from its online store. Ads for the devices have been removed from Apple's website's home page, and the watches are now "currently unavailable" on the site.

These models are also set to be taken off the shelves from its flagship stores by December 24th.

The halt in online sales comes after the International Trade Commission ruled that Apple violated patents from Masimo, a health-tech company, related to blood oxygen monitoring. Both of the watches being pulled from shelves have a feature that tracks the wearer's blood oxygen levels.

When the ban goes into effect, Apple will be barred from importing Apple Watches from overseas.

Pulling sales of these models could cost Apple between $300 to $400 million in lost revenue. The iPhone maker says it's currently taking measures — like updating its software — to resolve the issue related to the blood oxygen monitor, according to Bloomberg. Apple has also said it will try to fight the ITC ruling.

Masimo told Business Insider that the ruling "demonstrates that even the world's most powerful company must abide by the law."

Separately, Apple will no longer replace out-of-warranty watches, Bloomberg reported. That includes models going back to Apple Watch Series 6, which include the blood oxygen feature the commission ruled were covered by the patents.

Apple, when contacted by BI, didn't say whether it plans on putting its latest watches back online in the near future.

The ITC ruling came after Masimo sued Apple for patent infringement related to its pulse oximetry technology in 2020.

"This is not an accidental infringement," Joe Kiani, CEO and founder of Masimo, told Bloomberg. "This is a deliberate taking of our intellectual property."

Kiani also claimed that the tech giant poached 25 of the medical company's engineers, including its chief medical officer and the CTO of a spinoff company.

Kiani said he is open to reaching a settlement with Apple. If the two companies don't settle, Apple's only other hope is to either get President Biden to veto the ruling, which is unlikely, or to convince customs officials that a software tweak addresses the issue without having to make any changes to the device's hardware.