110mm brakes are made for wide freeride and powder skis with a waist width between 93mm and 108mm. If your skis fall in that range, you'll want the 110mm option — the brake arms need to clear the ski's width to deploy properly and do their job of stopping a runaway ski after a release.
The catch is that 110mm brakes create noticeable drag if you use them on narrower skis. When you carve a turn, the brake arms can catch in the snow, which feels sluggish and can even throw off your edge control. So if your skis are narrower than 93mm at the waist, step down to a 95mm brake instead.
The sweet spot is matching your brake width to your ski's waist plus about 5-15mm of clearance. So for a 100mm-waist powder ski, 110mm brakes are right in that window — enough room to deploy cleanly without excess overhang.