Amazon is no longer selling new versions of the Apple Watch Series 4 and Series 5 models through its online store in the United States, with the listings disappearing earlier today.

There is no word on why Amazon has pulled Apple Watch Series 4 and Series 5 models, but these are the Apple Watches that feature ECG functionality. All models, capacities, and colors are missing from Amazon's storefront.

Amazon is continuing to list refurbished Apple Watch Series 4 and Series 5 models from third party sellers, but there are no new models available nor models available direct from Amazon. Attempting to visit a page that previously had a Series 4 or Series 5 Apple Watch listed results in an error message

The Apple Watch Series 3 and other Apple products like iPads and Macs continue to be available from Amazon, so this issue is limited to newer Apple Watch models. Should we learn more about why Amazon has pulled Series 4 and Series 5 Apple Watch listings, we'll update this article.

Update: A few hours after removing all Apple Watch Series 4 and 5 listings, Amazon has returned the products to its online store.