Rhythm Mohair Button Up Shirt. The Mohair Button Up Knit, washed for a vintage hand feel, is Rhythm's latest collared knit polo. It's collar, sleeves and waist come ribbed for a more comfortable fit, designed as a dual attempt at style and warmth. Made with a Mohair blend and button front closure, the Mohair Button Up Knit is layering essential. Tonal logo embroidery at left chest. Sleeve cuffs and body hem. 47 ACrylic 30% Nylon 15% Wool 8% Mohair. Imported.