This property called spell channeling works on weapons and shields so that no casting will disarm you. All spells can be casted with a spell channel weapon and it wont disarm. If you have mage weapon with this property you can cast spells and your defense will match that of someone with a fighting skill equal to your Magery. Spell channeling usually is accompanied by a Faster Casting of -1 which will make you cast slower if you fall below 2. The list below has all of the UO items with spell channeling on them.