What´s the difference between Atlas Armlet and Hyper Wrist?

I think both of these things increased Vigor, but they´re described differently.
What´s with this Atlas Armlet "raises attack power" and Hyper Wrist "raises Vigor" thingy?
This is just like some random, non-existent Relics like Holy Wall "raises defensive power" and Turtle Shell "raises Vitality" just to give an example.
What´s the matter with the earlier Relics?
What´s the difference?

This is how I always understood it. You have the Atlas Armlet and Earrings, which increase your attack power and magic power (i.e. physical damage and magical damage) and the Hero Ring which increases both. Now I've always wondered if equipping two Atlas Armlets or two Hero Rings has the same effect as two Earrings, but I've never tried.

The Hyper Wrist increases your Vigor, so all things associated with Vigor, not just physical damage, get a boost.

While two earrings will conseculatively stack, two Atlas Armets won't. Same goes with Hero rings (although two Hero rings/Hero ring and Earring will have the same effec as two Earrings). Basically if your vigor is equal or above 128, then further Vigor will do nothing to your attack damage. There's a lot of stuff to consider, so I suggest you head over to GameFaq's FF6 section and look up the Algorithm's FAQ.