Colloquially referred to as "angel cuffs", these handcuffs are etched with various sigils that act as binding links to nullify the powers of angels. Despite being referred to as "angel cuffs", the sigils eteched into them also are effective in restraining demons and reapers. They prevent the entities from using their powers, reduce their strength, prevent teleportation and in the case of demons and angels prevent them from vacating their vessels.
Archangels have shown an immunity to the spellwork on the handcuffs, and are typically able to shrug them off. However, Bobby was able to modify the sigils on the cuffs, making them capable of temporarily restraining an archangel's powers, including Michael.
Crowley is once again shown to be locked up the Bunker's dungeon when he meets the Wicked Witch of the West, who is unable to free him from his restraints, as the dungeon is warded against all supernatural beings.
Crowley is still locked-up in the dungeon, wearing the handcuffs.
Crowley is freed from the Men of Letters dungeon, to help expel Gadreel from Sam's body, but only on the condition he needs to wear the binding handcuffs. Later when he talks to Cecily, he shows her the cuffs and asks if they can be removed, to which she replies "Not without the key." Later, Crowley also wears a collar that apparently serves the same purpose as he can't leave his meatsuit with it on.
After finding Crowley addicted to human blood, Sam and Dean slap the handcuffs on him to force him to detox.
The handcuffs are used on Gadreel, when he is captured by Sam and Dean.
When Dean confronts the reaper Tessa, and realizes she has carved an Enochian rune in her chest, and plans to "blow her self up." He is able to place the handcuffs on her before a fight can ensue between the two.
Dean is still in the handcuffs when Sam places him in the devil's trap in the Bunker's dungeon. Dean is later able to slip out of the handcuffs, as well as out of the devil's trap when he becomes human enough.
Metatron is hauled out of Heaven's prison in a pair of handcuffs, etched with binding sigils.
Though he is now human, Metatron is still shackled with the handcuffs.
To keep Lucifer in check, Castiel forces him to wear angel cuffs to keep his power bound. Lucifer agrees, but when the group comes across a contingent of angels, Lucifer smites them with a snap, and reveals that the cuffs do not work on him as they melt off his wrists.
After Bobby did some tinkering with the angel cuffs, he was able to improve the angel cuffs allowing for them to hold an archangel, and giving Sam a chance to restrain Michael and bring him to the Bunker.