This is different from the Series 7, Series 8 ... Watch Ultra and Ultra 2 each feature a 49mm case. However, straps that fit 44mm/45mm/46mm Apple Watch models will also work with the Ultra ...
Older versions, like the Apple Watch Series 3, came in 42mm and 38mm case options ... while the Series 7, 8, and 9 are available in 41mm and 45mm sizes. So while it’s technically possible ...