A blue power ring(along with the Blue Lantern Corps) were formed following the Sinestro Corps War by Ganthet and Sayd.
Abilities of the Rings
As a conduit of power from the blue range of the emotional spectrum, the Blue Power rings have a number of abilities akin to those of other Lantern Rings. The Ring is a source of limitless power, and thus there is no limit to what it can do, but here are some abilities it has been shown to have. The only limitation with the Blue Lantern Ring is that it is basically useless when not in the presence of a Green Lantern. In such situations, the rings can only enable Blue Lanterns to fly and be protected from the ravages of space.
- Animating: A Blue Lantern can will things to move how he wants.
- Hope Constructs: The rings can construct anything the wearer can imagine from hard-light energy, as long as they are willing to make it. The more determined the wearer is, the more complex and intricate these things can be. The constructs can even be so complex as to form working machines, computers, and even people.
- Artificial Intelligence: Every ring has a connection to the Main Battery on Odym, which taps into an artificial intelligence. It acts as an "on-board computer," telling the wearer what they need to know. It can either respond out loud, or silently directly to the wearer's mind. The AI contains a large database of information that may be crucial to a Lantern's success. The ring also translates nearly every language to and from the wearer, which is why the Corps can communicate with each other. When the bearer of a Blue Lantern ring dies, the ring will seek out a suitable replacement for their sector.
- Burglar Alarm: A Blue Lantern can coat anything with the ring's beam and thus, if anyone other than himself touches it, his ring will glow, alerting him to the possible theft.
- Communicator: The ring can act as a personal communicator between Blue Lanterns. They have also been seen connected to telephones.
- Costumes: The wearer of the ring may create any costume they choose, based on their personal preferences, whenever they choose. The ring projects the costume over any clothes already worn at the time.
- Energy Projection: The rings can also project beams, form protective bubbles and force fields, and fire destructive blasts. Sometimes, depending on the wearer, the beams and blasts make sounds.
- Flight: The ring allows the wearer to fly in atmosphere or in space, and can achieve incredible speeds, moving from planet to planet in a matter of hours.
- Invisibility: The ring can make the wearer or anything else invisible.
- Intangibility: The ring can make the user or others intangible, thus allowing the wearer to pass through solid objects.
- Matter Manipulation: A Blue Lantern can use their ring to manipulate nearby matter, such as water, for various purposes such as a construct that acts like an energy construct but can block something yellow and may serve a purpose that an energy construct couldn't perform.
- Mind Control: The wearer of the Ring can use it to plant post hypnotic commands or control a person. It can also probe the Lantern's or another person's mind, allowing the ring to uncover memories or the person's thoughts. The ring also possesses the ability to project illusions for the purpose of distraction.
- Power Absorbing: In the JLA's first fight with Amazo, it was GL who defeated him by drawing out all of Amazo's powers. In Green Lantern/Silver Surfer: Unholy Alliances, Kyle defeated Parallax with SS' power and Thanos with Oa's energy by drawing out all that extra energy from them which made them unconscious. However he couldn't hold all that power nor could his Ring like Hal did with Amazo's powers, so that move isn't often used with so much power.
- Radiation: Besides light based radiation used to create the energy constructs associated with a Blue Lantern, the ring can simulate various forms of radiation. One example of this is the ability to simulate the radiation of Green Kryptonite, a form of radiation that is harmful to Superman.
- Ring Duplication: Each ring can duplicate itself, creating a second ring which may be given to another as a backup, for protection, or to help the lantern in times of great need. This duplicate ring must is exactly like a normal ring.
- Temperature Control: The Ring can increase or decrease the temperature of anything, even something as large as stars, or even create bubbles of intense heat or cold, even down to Absolute Zero.
- Transforming: The ring can transform anyone or anything, be it into an animal, altering their state of appearance, or their size. Once Hal and Alan turned the two Flashes (Barry and Jay) to light protons in order to free them from prisons.
- X-Ray: The ring can allow the user to see through walls, without the people on the other side knowing.
Unique Powers & Abilities
It appears that each new Lantern Corps Ring as unique abilities. The Blue Rings are, so far, unlike any of the rings of the other corps. For Blue Power Rings, these abilities include:
Hope Empowerment & Manipulation
When a different Lantern is near the aura of a Blue Lantern, their ring will be charged up to maximum capacity and will remain so as long as that Blue Lantern "hopes for [his or her] well-being". The constant empowerment has a tendency to cause a form interference to other power sources. Blue Lanterns feed off of hope and can utilize its energy for a variety of effects, bypassing using the rings energy. For example, Saints Walker and Warth use the hope of a planet's billions of alien beings to reverse the age of a dying sun 8.6 billion years.
The Blue Rings are powered and fueled by hope, so there is no need to recharge them with a battery.
Unlike the other Lanterns, the constructs produced by the Blue Lantern's are in response to the target's psychosis, as opposed to what the ring's bearer wanted create. Otherwise the ring is a weapon capable of transforming the wearer's thoughts into physical constructs via the wearer's mastery of hope. A Blue Lantern can create any particular items or construct that they can imagine as long as they have the mastery of hope necessary to conjure it into existence.
Apparently, Blue Rings can heal physical, spiritual, and mental wounds. The Blue Light is also the only known thing that can extinguish the fire produced by Red Lanterns.
Hope fuels willpower, and as such Blue Lanterns empower Green Lanterns. Since hope is useless without the willpower to enact it, without a Green Lantern ring nearby, a blue power ring is useless. When not in the presence of a Green Lantern Blue lanterns are limited to flight and generating protective auras.
Cancel out the effects of the red power ring
The Blue Rings are also capable of destroying The Red Rings if one is placed on a Red Lantern. Whether this unusual process can be reversed is not yet known.