one of a kind

/W AH1 N AH0 V AH0 K AY0 N D/
noun
  1. 1

    A unique specimen.

    โ€œThis fireplace is one of a kind. You won't see another like it anywhere else.โ€

Synonyms

Source: https://en.wiktionary.org/wiki/one%20of%20a%20kind