A ring of mage armor was a type of enchanted ring, appearing as a simple band of precious metals embedded with three large blue gemstones. Often employed by spellcasters not trained in wearing armor themselves, they contained innate abjuration magic that could be unleashed with a command word. This effect could be used once, recharging at dawn.
The user was enveloped in an invisible force field that protected them in much the same way as mundane armor, but without restricted movement or weight. Because it was a force field, incorporeal creatures or objects could not pass through it. This magic force armor would last for at eight hours.