The perfect casual dress for any evening dinner or business meeting, will fit anywhere from a 4’ 10 to a 5’ 4-5’ 7 COS sizing is notoriously "generous" and often runs large. A COS Size XS is technically a US 4 but is designed with a relaxed, boxy fit. Chest: Fits up to 31.5"–33".Waist: Approximately 25"–26".Hips: 34.5"–35.5".Length: For a standard polo dress, the back length is roughly 35"–36". “Tagged XS but fits more like a modern Small (US 4-6) due to the relaxed COS cut."