This is a vintage black nylon tricot knit robe or open kimono jacket by Undercover Wear, probably from the 90s. Solid black silky nylon knit top has lace trim at the open front, hem and at the wrist on the long sleeves. No belt included.
 
Pre-owned, used; in good condition with no noted flaws.
Marked as size S or small. Please read the actual garment measurements given next--
Bust- approx. 38" around at the underarms, with the front edges not quite touching
Pit to pit- 19" across
Center back length- 27 1/2"
Sleeve length- 23"