Sui Generis is latin for "one of a kind"
But what does it mean? A person or thing that is unique, in a class by itself. It is a phrase that means "of its (his, her, their) own kind; in a class by itself; unique.
This gold necklace says "sui generis" in the front and in the back it has some dots embellishment,
metal: 14K yellow gold, cable chain 16" long