Spell Channeling is an item property that allows Magery spells to be cast without unequipping the Right and Left Hand equipment slots. It is always accompanied by a FC penalty of -1 (which does not count as an additional property), though this may be cancelled out if the item has a FC bonus as well. (If you don't see a penalty/bonus, then your casting rate remains the same.)
For example, an item displaying spell channeling with a FC of -1 has a single property. A spell channeling item seemingly without the penalty has at least two properties. Keep this in mind when crafting magic items.
Spellbooks do not require spell channeling in order to stay equipped while casting. Wands always have this property.
Items which break the normal rules:
Event and Quest Items
The following resources are required to imbue Spell Channeling: