Diana's silver bracelets were created from the remains of Zeus's Aegis, itself an impenetrable shield formed from the goat Amaltheia, who wet-nursed the infant Zeus, thus providing the energy from which Olympus sprung. Zeus´s father Cronus splintered the shield, and Athena had Hephaestus forge the remains into a great prize to be awarded to the worthiest of all Amazons, their greatest worshippers. The bracelets are unbreakable, and Diana is swift enough to deflect bullets with them. Furthermore, When Diana crosses them to protect her from impact with larger projectiles as well as damage inflicted by explosions and collisions with hard surfaces, the bracelets generate a small energy shield. The Bracelets are even able to deflect Omega Beams (Darkseid's Omega Effect, Superman/Batman issue 13) and heat vision (Supergirl, Superman/Batman issue 9). During the destruction of Olympus following an attack by Darkseid, the bracelets were shown to be durable enough to even withstand a blast from the destructive energies of the gods which Diana had to direct.
They can also be used used offensively as well by slamming them together. The resulting effect has been shown to temporarily incapacitate even Superman. Recently, because the bracelets were forged from Zeus's shield, Diana has unlocked the ability to discharge electricity from her gauntlets.
In the golden age if Diana's bracelets (or those of any Amazon) were bound by a man it made her lose all her powers. At other points in the golden age the bracelets were demonstrated as the only thing which restricted an Amazons from unleashing her full power in a berserker-like rage. Like the rest of her items in the golden age, the bracelets were made out of Amazonium, a nearly indestructible metal. Unlike their modern depiction though, the bracelets in the golden and silver age could be destroyed as occurred on certain occasions.
The bracelets change in appearance slightly between artistic interpretation, from either larger than usual wristbands to almost wrist to elbow covering armbands. In some occassions the bracelets are decorated with a red star.
In the comic "Wonder Woman Amazonia" the bracelets are decorated with a Victorian style.
On occasion in her publication history Diana has not worn the bracelets (such as during her depowered phase in the 1970s).
In other media
Wonder Woman's bracelets appear: Wonder Woman (TV Series) (1975-1977), Justice League Animated Series (2001-2006) and Wonder Woman Animated Film (2009).
In the 1970's TV series the metal of the bracelets is call Feminum but in the original comics it was called Amazonium.