Hardedge & Carbon Bangle - Steal in Shinra Building
On the 67th and 68th floors of the Shinra Building you'll have a chance of running into two different enemies that you can steal extremely good equipment from. Moth Slasher C and Soldier: 3rd A are the two enemies I am talking about.
The Soldier: 3rd A enemies can pack a punch if your group is lower level but it won't take long of grinding here to gain a few levels and make all of these encounters a piece of cake. You'll need to fight more of the Moth Slasher C enemies than the Soldier: 3rd A ones anyway since the Moth Slasher enemies are who you steal the armor item from.