Having trouble with cloak of protection in DDB

I have a character with a cloak of protection. It is in my equipment and is marked as "In Use" but the bonuses aren't getting included in AC or in Saves. Is there something more I need to do to get it to work?

The Cloak of Protection requires attunement. Scroll down to the attunement section, and make sure the box next to it is checked off down there.

I don't see that option. Do I have to have bought a specific book for that to work?

http://www.gazellesoft.com/cloak.png

If you have the item on your character sheet, there should be an attunement section at the bottom of the inventory page

Awesome - it's working. Thanks for the help.