The only problem with the Apple Watch’s unprecedented ubiquity ... For the Series 4-6, case sizes were 40mm and 44mm, while the Series 0-3 were 38mm and 42mm. It can sound confusing, but ...
The Apple Watch Ultra 2 is the top-of-the-line model of Apple’s wearable devices, featuring a beautiful titanium design, a gorgeous display, and unparalleled performance with the S9 chipset.
If you have the smaller variant of the Apple Watch, a 38mm, 40mm, 41mm, or 42mm band from that size lineup will fit any watch. Likewise, any larger band for the 44mm, 45mm, 46mm, and 49mm range ...