The holidays are usually the busiest shopping season for technology companies like Apple as customers rush to get the latest and greatest gadgets. This year, however, Apple’s newest smartwatches — the highly anticipated Series 9 and rugged Ultra 2 — are notably absent from the company’s online and retail stores across the United States.

After December 24th, it is no longer possible for American shoppers to purchase Apple’s newest flagship wearable devices. This comes as the result of a US import ban on the watches set to fully take effect on December 26th. The ban was imposed by the US International Trade Commission (ITC) due to an ongoing patent dispute between Apple and medical device maker Masimo Corporation.

At issue are Masimo’s patents related to measuring blood oxygen saturation (SpO2) levels using sensor technology. Masimo argues that the sensor system inside Apple’s newest watches infringes upon these patents. The ITC agreed with these claims in a recent ruling, denying Apple’s motion to delay the import ban while it appeals the decision.

Apple has complied by pulling all models of Apple Watch equipped with SpO2 sensors from its online and retail stores in America, including special Nike and Hermès editions of the Series 9. This also impacts refurbished models of older Series 7 and 8 watches. Only the more affordable Apple Watch SE without the SpO2 sensor remains available for sale in the US. International sales do not seem to be impacted at this time.

It is unknown how long the ban may remain in effect and block access to Apple’s latest wearable innovations on the American market. Apple is reportedly considering multiple options — technical, legal, and negotiating a settlement with Masimo (though talks have not yet begun as of December 19th).

Related: Patent battle leaves Apple Watch owners without repair options

Bloomberg reported Apple engineers are working on software updates to work around Masimo’s patents and avoid further infringement. But hardware redesigns could take months and would likely be necessary if the dispute focuses on the physical sensors rather than just algorithms as Masimo claims.

In a December 19th statement, Apple said it “strongly disagrees” with the ITC ruling and is “pursuing a range of legal and technical options to ensure that Apple Watch is available to customers.” For now, however, American consumers eager to get Apple’s cutting-edge smartwatch technology for the holidays are out of luck.