How to find out if an Apple Watch Series 9 model has the blood oxygen feature available

As of today, all new Apple Watch Series 9 and Ultra 2 models sold by Apple do not support the blood oxygen feature. This is due to an ongoing patent dispute with Masimo. But if you are buying an Apple Watch from eBay or a third-party retailer right now, how do you know if your watch will have the blood oxygen feature enabled or not?


To clarify, the new watch models being sold still have the blood oxygen sensor hardware inside them. In fact, the watches seem to be physically identical aside from updated part numbers. Rather than making permanent hardware changes, Apple has disabled the feature through the watchOS software.

The Blood Oxygen app will still show up on the home screen of impacted watches, but it will refuse to run a scan and instead an error message will say “The Blood Oxygen app is no longer available. Learn more in the Health app on your iPhone”.

Perhaps you are scrambling to buy a Series 9 today before the old stock runs out. But ahead of purchase, if the watches are identical, how can you tell for sure whether the model you are buying is affected?

How to find out if your Apple Watch Series 9 model supports Blood Oxygen?

The way to find out if the Apple Watch you are buying has blood oxygen feature disabled or not is by checking the part number. Apple says that new watches with blood oxygen disabled have part numbers that end with the string ‘LW/A’.

You can see this part number on the label of the Apple Watch box. It is an eight character code of capital letters and numbers, that also includes a slash before the last character.

You can also check on the watch itself, if it is set up. Perhaps you are buying used from eBay. Open the Settings app on the Watch, go to General -> About and scroll down to where it says ‘Model’. By default, it will display the model number, like A2978, not the part number. Tap the text to toggle to view the part number.

This is also viewable through the Watch companion app on their paired iPhone. Go to General -> About -> Model Number, and you can also tap the text here to toggle between model and part number.

Does the ban affect my Apple Watch Series 9 if I already bought it?

No, the ban does not impact already sold watches. If you have an Apple Watch today and the Blood Oxygen feature is functional, it will continue working as normal. Only new watches sold with part numbers ending LW/A are affected.

As these new model watches still have the blood oxygen sensors inside the case, and it is merely disabled by software, it is possible that eventually the feature will be re-enabled. Apple is currently taking its patent infringement case with Masimo to the US Court of Appeals. But it could be many months before the court arrives at a judgement, and Apple isn’t guaranteed to win. It is also possible that Apple and Masimo agree to a private settlement at some point.

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