Minecraft: 1.12.2
Forge: 14.23.5.2838

Mods: 1
TheBetweenlands-3.4.11-universal

Unsure if intended but it seems that any Unbreaking Enchantments won't work on the Ring of Power. For a test I equipped two Rings of Power but one of them has an "Unbreaking III" enchantment and let them sit for awhile. Here's what the durability shows...

Note: I tried to equip/unequip them at the same time.

No Enchantment
1530 / 1800

Unbreaking III
1529 / 1800

This also occurs with the Ring of Summoning but not the Ring of Ascent & Recruitment since they use XP directly, unless they automatically drain your XP to keep the Ring charged or something.

Certain other items like the Item Magnet & Bark Amulet the Unbreaking Enchantment does appear to work with those.

One more thing to mention is that if the Ring of Power reaches 0 durability and they're still equipped... they still apply the damage boost. Some tests using a Diamond Sword on Cyclic's Target Dummy with Damage Indicators...

2x Ring of Power with Durability
14 Damage

2x Ring of Power with NO Durability
14 Damage

After thinking about it some more I think that it's ok that it constantly uses XP when equipped since it's such a powerful item. However the ring now also gives the player a slight speed boost when worn to better reflect that the ring is always active (i.e. is just giving the player a general boost in strength, including mobility)

One more thing to mention is that if the Ring of Power reaches 0 durability and they're still equipped... they still apply the damage boost.

Huh, you're right. That's quite an oversight, thanks :P

Unsure if intended but it seems that any Unbreaking Enchantments won't work on the Ring of Power.

That's intentional. The item isn't really damaged, the bar is just used as a means of showing how much charge is left.

Ah, would it be possible to have the Ring of Power charges become used as you damage mobs instead of the charges draining just for being equipped? The charges & repair costs could be changed for balancing reasons.

No, it's not because I forget to unequip the ring or something, nope.

Hm yeah, maybe