Powers and Abilities
Kara's bracelet is seen to possess just one power, based on the advanced Kryptonian technology it houses.
- It is shown to repel certain hostile entities away from its wearer, using a bright light, as Kara is able to use it to repel Darkseid away from herself and Clark. (Supergirl)
When Kara lost her memory and her powers, the bracelet was her only link to her Kryptonian past. When she was in Detroit, Michigan, Kara dropped her bracelet while being chased by Jacob Finley; Lex Luthor found it, but soon after was shot by Finley. The bracelet turned up later in Lionel Luthor's vault; presumably, Lionel found the bracelet when his son was transported from Detroit to Smallville.
Because Lionel was an emissary of Jor-El, he knew about the capabilities of the bracelet. And during the coming emergence of Brainiac, he wanted to insure that the bracelet would not fall into villainous hands. However, the true intentions that he could discuss with Clark had never made it to the surface.
Lex blackmailed Pete Ross, who had gained stretching powers from kryptonite-irradiated chewing gum, into stealing the bracelet from Lionel. Clark Kent stopped Pete from giving it to Lex, but Pete overpowered him with kryptonite and went to see Lex anyway. However, Pete left the bracelet behind, and Clark retrieved it. Lex then had his henchman torture Pete for information about the bracelet, but Pete (showing his loyalty to Clark) refused to give it up. Clark saved Pete, and knocked out Lex and his henchman.
Because Kara had lost her memory, Clark was afraid to give back her bracelet, worried that it might trigger memories about her past that Lex could then find out. He thus hid the bracelet under the floorboards of his barn.
When Clark and Lois were trapped in the Phantom Zone, they were both attacked by a cloaked figure who knocked Lois out. The figure advanced on Clark, but Clark grabbed its wrist and was shocked to recognize Kara's silver cuff bracelet.
- The bracelet is engraved with the House of El symbol, which represents Kara's relationship with the El family. The bracelet is used as opposed to the well known "S" symbol displayed on the chest (like Clark's Blur outfit) signifying that Kara isn't quite Supergirl yet. 
- In a deleted scene from Veritas, Brainiac needed to use Kara's bracelet to get back to Krypton. After the writer's strike, this scene was replaced and it was explained that the Fortress of Solitude had actually opened the time portal back to Krypton. 
- Kara's steel cuff bracelet is similar in appearance to Wonder Woman's deflector bracelets, as seen in the following photos. This is likely a reference to how in Post-Crisis continuity, Kara spent time training with the Amazons.
- Lara was seen in a hologram with Jor-el wearing a silver bracelet is engraved with the House of El symbol, which represents Lara's relationship with the El family. This can also be seen as a tongue in cheek reference to Lara playing Supergirl/Kara Zor-el in 1984.(Abandoned)