Not all Apple Watch bands are available in all sizes and not all are compatible with both models. The modern buckle, for example, is limited to the 40 and 41 mm models, but for the most part Apple Watch straps fit a wide range of wrist sizes. More than a year ago, Apple announced plans to search for child sexual abuse material (CSAM) with the release of iOS 15.2.You don't need to be so careful with the other Apple Watch bands, but it's helpful to get accurate measurements to ensure a good fit. But many of them no longer include options for the 38, 40, 42 and 44 mm size options for all straps.
Apple offers Apple Watch Series 7 in 41 mm and 45 mm case sizes, and Apple Watch SE in 40 and 44 mm size options. Contrary to some rumors prior to the event, the redesigned Apple Watch Series 7 will not require new watch straps and will continue to be compatible with all previous watch straps. With the Apple Watch coming in so many different case sizes, it's no wonder people get confused as to which of the different watch bands will fit the watch they have. While it may seem at first that Apple has unceremoniously eradicated support for all previous models, don't worry, it didn't.
For the most part, each Apple Watch band has a good size range, and you just need to pay close attention to whether your wrist is smaller than average or larger than average. Getting a larger Apple Watch band basically ensures that it will work with previous wearables that were the larger size option of their respective generation. Both bands have an elastic quality that allows them to slide over one hand and contract at the wrist, and these bands stretch over time, so it may be worthwhile to reduce the size of the measurement. For this band, Apple says the size starts at 130mm, but there is some margin here due to the tight fit, so it's also a good choice for smaller wrists.
If you're preparing to buy an Apple Watch, you should consider the wrist size and strap options available to get the best fit. The watch comes in a new case size of 41 mm and 45 mm, moving away from the 40 mm and 44 mm size that has been the standard of the last generations of Apple Watch. The Apple Watch Series 7 didn't receive the expected flat-edge redesign, but it will come with a larger body. However, just like all previous bands fit the Apple Watch Series 7, these 41mm and 45mm straps are compatible with previous watches.