Walk range of motion measures how far the boot's cuff can rotate forward when you switch into walk mode—think of it as how naturally you can stride when you're not clipped into your ski. It's measured in degrees, and more range means easier skinning, hiking, and general travel on foot.
For dedicated backcountry touring where you're spending hours skinning uphill, look for 50 degrees or more. Freeride boots that balance uphill and downhill performance typically offer 25–40 degrees, which is plenty for short hikes or sidecountry laps. Resort-focused boots with a walk mode usually sit around 15–25 degrees—enough to shuffle to the parking lot but not meant for real touring.
Don't assume that a higher walk range automatically means worse downhill performance. Modern touring boots can deliver both excellent cuff rotation for the up and solid stiffness for the down. Match the range to how much time you actually spend going uphill, and you'll be set.