Unlike the Green Rings of the Corps which operate by channeling pure willpower, these rings which are forged on Qward channel pure fear. Several versions of these rings have been created, but recently they have become the primary weapon of the Sinestro Corps, seeking out individuals to battle the Green Lantern Corps who have the ability to instill great fear.
Abilities of the Rings
As a conduit of power from the yellow range of the emotional spectrum, the Yellow (Sinestro) 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.
Animating: A Sinestro Lantern can will things to move how he wants. The object moved however is often covered in a yellow aura.
Artificial Intelligence : Every ring has a connection to the Main Battery on Qward, which taps into Parallax. 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 "Sinestro'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 Sinestro Corps ring dies, the ring will seek out a suitable replacement for their sector, someone capable of instilling great fear.
Communicator: The ring can act as a personal communicator between Sinestro Lanterns.
Costume Creation: It varies based on species type, anatomy, and personal preference. But as long as it contains the yellow and black colors and yellow lantern symbol, it is acceptable within the Sinestro Corps. The ring projects the costume over any clothes already worn at any given 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.
Yellow Energy 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.
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. Via wormhole creation, the wearer can travel to other solar systems.
Invisibility: The Sinestro Corps ring has the ability to make the wearer or others invisible due to the ring's ability to manipulate the electromagnetic spectrum.
Intangibility: The ring allows the wearer to alter their density, allowing the wearer to pass through solid objects.
X-Ray Vision: The Sinestro power ring has the ability to see through all objects without others around him/her being aware that the object has been made transparent. Not all material can be penetrated though.
Mind Control: The wearer of the Ring can use it to plant post hypnotic commands or control a person.
Mirages: The Ring can create mirages/illusions.
Power Absorbtion: 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.
Probing: The ring can probe the Lantern's or another person's mind, allowing him to uncover memories or the person's thoughts.
Radiation: Besides light based radiation used to create the energy constructs associated with a Sinestro Corps member or a Green Lantern, the ring can simulate various forms of radiation. One example of this is the ability to simulate the radiation of Red solar radiation, which stunts or removes the powers of Kryptonians and Daxamites.
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(the point at which even subatomic particles cease to move).
Override: Sinestro secretly has an override command installed into each of the Sinestro Corps rings as a backup plan to ensure he can never be defeated by a member of his own Corps. The override inflicts severe damage on the wearer, allowing them to be easily over powered. Sinestro uses this method to defeat Mongul and take back his Corps.
Recharging: The rings need to be recharged by means of a Power Battery. Other large sources of power may be used to recharge a power ring, however effectiveness may vary. The internal power source of a Manhunter Android is, in effect, the same as a power battery, and can be used to recharge a power ring. During the JLA / Avengers crossover, a Cosmic Cube was used to recharge a depleted ring, although this is not an ideal solution and is available if there are no other options. Members of the Sinestro Corps they generally quote the Sinestro Corps oath while recharging their rings: "In blackest day, in brightest night, Beware your fears made into light! Let those who try to stop what's right, Burn like his power... Sinestro's might!” Unlike the Green Lantern Corps however each Sinestro Corps member seems to use a standard unaltered oath.
In principle, the first ring of Sinestro was made of a material called Qwadarmite. In the old days, Sinestro was to have enough of these. It would be the saga of Guy Gardner: Rebirth, when we learned that the ring was indestructible qwadarmite and to do so, had spent all the reserves of such material. So which material are rings made today? Do they have their origin in science or magic?
Besides this, there is another thing that should be taken into account, which is the way to recharge the ring. The former to reloaded the old ones was fighting a Green Lantern, whereas today use battery power, which feeds on fear. Thus arises this question: old rings used the willpower as a source of energy?
In the Green Lantern movie we see that the Guardians of the Universe forge a yellow power ring, and give it to their finest warrior, Thaal Sinestro, who intends to master the ring powered by fear and teach the rest of the corps to do the same in order to defeat Parallax, by using his own weapon against him. But the ring is never used because of Hal Jordan defeating Parallax. But we get to see a scene inbetween the credits revealing Sinestro placing the ring into his finger, his suit turning yellow and him rejoicing in the power of fear overcoming him.