Cotton/Silk/Cashmere Fair Isle Sweater Vest. With its storied heritage and iconic look, Fair Isle is a prep staple and a Polo favorite. Polo Ralph Lauren's sweater vest reinterprets the timeless motif with 11 luxurious yarns composed of cotton, mulberry silk, and cashmere. Material: 79% Cotton 17% Silk 4% Cashmere. Size S: Armpit to armpit: 19.5" ; Shoulder to shoulder: 16.5" ; Length (shoulder to hem) 26.5. Size M: Armpit to armpit: 20.5" ; Shoulder to shoulder: 17" ; Length (shoulder to hem) 26.5. Size L: Armpit to armpit: 22.5" ; Shoulder to shoulder: 17.5" ; Length ...