It is important to know your Apple Watch Case Size to ensure that your new band is a proper fit for your Apple Watch. Luckily, this is an easy process that can be done a couple of ways.
Method 1: Watch App on iPhone
Start by opening the "Watch" app on your iPhone
Select "All Watches" on the top left of your screen once in the app:
You can then verify the case / watch size of your Apple Watch:
Method 2: Back of Apple Watch
Case size is engraved on the back of every Apple Watch.
Placing Your Order
When placing your order, select the proper size from the drop down menu:
You would select "38mm, 40mm or 41mm" if your Apple Watch is:
And select "42mm, 44mm or 45mm" if your Apple Watch is: