The Equip Scroll item ability will switch through the available Item Sets within the specified category. This ability is generally used with a mouse scrollwheel so when the wheel is scrolled forward the next item set equips, and when scrolled backward the previous item set equips. The Equip Scroll ability doesn’t actually do the equip or unequip – it instead relies on the Equip Unequip ability to do the actual work.
The sensitivity for switching between items. The higher the value the faster the scroll wheel has to scroll in order to switch items.