Although the overall display of the newer iwatches is larger, the area where the strap attaches to the watch remains the same as the previous series for consistency in strap compatibility.

iwatch Strap Size Guide:
Compatible size  Iwatch Ultra Iwatch Series 4/5/6/7/8/SE
Compatible with Azmax's 49mm Bands 49mm case size  /
Compatible with Azmax's 44mm/45mm Bands 44/45mm case size