Vintage Gunne Sax by Jessica San Francisco Maxi Dress Juniors Size 5 
Tiered with lace trim 
Sleeveless  
Belt 
Lined 
Cottagecore Prairie 
The zipper does work - it's just too small for the mannequin to fully zip up 
Good pre-owned condition -  there are some spots and small areas of discoloration showing on the fabric associated with normal use and age - see pictures 

Measurements (taken with garment lying flat):
Chest underarm to underarm - 12.5"
Length down back from top of zipper -  app. 50"
Waist at seam - 11"