When you plan to order a new Apple Watch band, it is important to know your case size to make sure the band's adapter is correctly fits your Apple Watch. Remember "sizing" is based on your Apple Watch case size (not your wrist size).
While the case size is engraved on the back of every Apple Watch, it is often small and difficult to read. An easier way to find your watch size is to open your the Watch app on your iPhone.
In the app, click on “All Watches” (top left of the screen) as shown here:
When ordering your band from us, just select the appropriate size:
So select "38mm or 40mm if your Apple Watch is:
And select "42mm or 44mm if your Apple Watch is: