Series 4 Watches
I have several bands for the 42mm (series 3). Which series 4 will they fit?
42mm bands will fit the 44mm Series 4 Apple watch.
Band Compatibility
You can match a band with any Apple Watch Series 4 case of the same size. It also works with all previous versions of Apple Watch, including Apple Watch Series 3. The 40mm band works with the 38mm case; the 44mm band works with the 42mm case.