Vintage St John by Marie Gray Women Royal Blue Knit Dress Size 8

Vintage St John by Marie Gray Women Royal Blue special Knit Dress with back slit in great condition Size 8. The tag size is missing, but I know it’s size 8 or medium because the dress fits me and I wear 8 or medium. Also please refer to the measurements below. Approx measurements: Pit to pit - 18” Waist - 26” elastic Length from the waist - 26”