Zora Armor

Zora Armor is an item from The Legend of Zelda: Twilight Princess. It is the second set of clothing available in the game. While wearing the Zora Armor, Link can dive, swim faster, and breathe underwater indefinitely, like an actual Zora. The Zora Armor is necessary to complete the game, as it is needed in Lakebed Temple to retrieve the third Fused Shadow.

While wearing the armor, Link is more vulnerable to extreme heat and cold, including fire and ice-based attacks. If Link falls into the the icy lake of Snowpeak or the lava of the Goron Mines while wearing the armor, he will lose ten and twenty hearts, respectively. He will also take double damage from any other fire- or ice-based attacks, such as the Fire Arrows fired by Bulblins, or the spears of Chilfos.

The Zora Armor is considered the Twilight Princess version of the Zora Tunic, Zora's Flippers, and Zora Mask. It closely resembles the Hero's Tunic, but is blue, covered in scales, has a longer cap, features flipper-like boots, intricately engraved metal headpiece, and a pendant resembling the Zora's Sapphire, similar to the pendants are worn by Queen Rutela and Prince Ralis. While underwater, a strip of navy cloth covers Link's lower face, presumably filtering oxygen out of the water.

Obtaining
After clearing the Twilight from the Lanayru Province, Link heads to Telma's Bar in Hyrule Castle Town, where Prince Ralis is still in critical health and in the care of Ilia. Doctor Borville refuses to treat Prince Ralis because of a bias he has against Zoras, although he says he does not have the knowledge of Zora anatomy to treat him. The only way for Ilia to save the prince is by traveling to Kakariko Village to the village shaman, Renado. The Hyrulean Soldiers enthusiastically offer to help take them there, but flee when Telma says that they will likely encounter enemies. When the soldiers leave, she sees that Link is the only one left and requests his help.

After defeating King Bulblin a second time and escaping his horde of Bulblin Riders, the caravan finally reaches Kakariko Village. After Telma commends Link's courage, Queen Rutela's spirit thanks Link and asks him to follow her. She leads him to King Zora's Grave which contains the Zora Armor.

Theory
Given that the Zora Armor allows Link to breathe and swim underwater indefinitely, it is possible that it has Silver Scales (or perhaps even Golden Scales, though their coloration more strongly suggests the former) sewn into it, and it may also incorporate a Zora Tunic. This is potentially supported by the statement in the description that the armor is "made of the scales of fallen Zora warriors", as the proprietor of the Diving Game in The Legend of Zelda: Ocarina of Time states that the Silver Scale is, indeed, a genuine Zora scale, and the scales seen in the armor are silvery in color. It is possible that Queen Rutela's husband produced the armor by sewing Silver Scales into a blue tunic, while incorporating some light metal pieces to allow for defense.