Based on the search results, it seems that the Alpine Loop and the Trail Loop are both bands designed for use with the Apple Watch Ultra, but with different features and purposes.
The Alpine Loop is described as "light and comfortable" and is one of three 49mm bands designed specifically for the Apple Watch Ultra. However, the reviewer notes that they personally do not find it different enough from the Trail Loop. It is unclear what distinguishes the Alpine Loop from the other bands.
The Trail Loop, on the other hand, is designed with runners in mind, but can also be used by hikers and cyclists who want to keep weight to a minimum. It is made from woven nylon and fastens with a hook and loop closure (i.e. Velcro).
In summary, the Alpine Loop and the Trail Loop are two different bands designed for the Apple Watch Ultra. While it is unclear what distinguishes the Alpine Loop from the other bands, the Trail Loop is designed specifically for runners and is made from woven nylon with a Velcro closure.
