It's called "Chain Man" in "The Star of Grazing Sheep", which was designed by A Xing. It handcuffed a couple together like handcuffs. Although a little abnormal, they can fall in love. Of course, the story behind it is that A Xing and Vernon are both related to handcuffs: at first, they were handcuffed together all day, which was the beginning of acquaintance, and later they met and fell in love. After the separation, it was also because handcuffs were with Vernon. Finally, in the sea of fire, the two were handcuffed together again, and they swore to the death to fall in love again.
Therefore, handcuffs are the chain of fate between A Xing and Vernon, and they are also the witness of their love!