This is a pretty vintage half slip with elastic waist. Made of pink nylon tricot knit, it's finished with an ecru & green floral lace at the hem.
 
Pre-owned, used; in good overall condition EXCEPT FOR a couple of spots that didn't come out when I washed the slip. I didn't use a stain remover.
 
Marked as a size S or small. The actual garment measurements are given next--
Elastic waist- stretches from 24" up to 32" max
Hem- 44" around
Length- 20 1/2" from waist to hem