Features:
Concealed back zip
Stretchable 
Ribbon Strap non-adjustable
 
Measurements in last pic!
(If in between sizes: recommended to size down)
 
The model is 170cm, fits into UK6-8 clothing sizes, typically wears a size S.
Her pit-to-pit is 32", waist 25", wearing size S. 
 
Please allow for up to a 0.5-inch difference due to potential variations in measurements.