The Spell Channeling property allows Magery spells to be cast without unequipping the weapon, shield, or other item.
Often, spell channeling is accompanied by Faster Casting -1, meaning that the item will reduce the caster's casting speed. Some however, spawn without Faster Casting -1, and thus have no effect on the caster's casting speed. (Sometimes these items are still sought after, the decreased time being compensated for by other items. For example, a weapon with Faster Casting -1 can be balanced out by having a ring with Faster Casting 1 and the Ornament of the Magician which has Faster Casting 2, for a "total" Faster Casting of 2, the maximum for magery, despite the -1 penalty from the weapon.)