Ring of Renewal is an accessory in Final Fantasy XII that gives the user automatic Regen status, incrementally boosting the wearer's HP in a continuous way: the amount increased is a random amount from 1 to the unit's level every 1.5 seconds. It also gives +6 and +5 boosts to Defense and Magick Resist, respectively, and cancels out the effects of Sap, even from the Ensanguined Shield.
In the original PlayStation 2 versions, the Ring of Renewal can be bought in the "secret shop" in Necrohol of Nabudis for 18,000 gil after the party has the Treaty-Blade. It is also found in a treasure in Henne Mines' Phase 2 Dig (60% to appear, 50% chance to hold item, 50% chance the item is Ring of Renewal without Diamond Armlet equipped ), and Pharos - Third Ascent's Spire Ravel - 2nd Flight (55% chance to appear, 50% chance to be the Ring of Renewal with the Diamond Armlet ). It is the rare poach from the Deadly Nightshade.
The Ring of Renewal is the reward for completing the "Ann and her Sisters" quest aboard the skyferries, which can be completed when all skyferry routes are available after the events at Draklor Laboratory are complete; the player needs to travel each route and talk to the chief stewardess in the leisure craft.
In the updated Zodiac versions, the Ring of Renewal can't be bought from normal shops, but does sell for 9,000 gil. The ring is found in a treasure in Great Crystal's Uldobi Phullam Udiipraa (100% chance to appear) and in Pharos - Subterra's Penumbra - South (20% to appear, but is always the Ring of Renewal). It can be rarely stolen from the Shield Wyrm in Trial Mode Stage 67. It is still the rare poach from the Deadly Nightshade and the reward for the "Ann and her Sisters" sidequest.
Having automatic Regen status is useful for survivability; though the player can replicate the effect with Self:Regen or Ally:Regen or similar gambits, having the accessory equipped means the player can enter any encounter with Regen already in place and does not need to waste turns and MP for casting. Equipping the ring also nullifies the effects of Sap. However, the Regen spell is superior in that it heals Sap and applies Regen in its place, whereas with equipment that give Regen, the player can have both effects at once. Other equipment pieces that give constant Regen effect are the Renewing Morion light hat and the Ribbon accessory in the Zodiac versions.
It is worth finishing the skyferries sidequest as soon as it can be done to get the Ring of Renewal, unless the party already has Bubble Belts, which is the superior accessory to keeping HP up.
In a New Game Minus playthrough in the Zodiac versions, Regen restores minimal HP as it scales off the afflicted's level, but the Ring if Renewal could still be used to immunize against Sap.