Cardi B Just Bought Her Boyfriend OFFSET An AFTER-BIRTHDAY Gift . . . A Diamond Chain Shaped Like NATURE BOY RIC FLAIR!! (PICS)

Last week was rapper Offset's birthday - and he got a nice COME UP, courtesy of his girlfriend Cardi B.

Cardi bought her man a new Rolls Royce Wraith.

And there's more. After his birthday - Cardi wanted to make sure that her man still felt special, so she bought him the below diamond Ric Flair piece.

It costs about 70 RACKS!!

Here's Offset's chain:

Offset turned 26 on December 14. He and Cardi celebrated with a crazy, over the top birthday party in Los Angeles.