Gunmetal Finished Shank Style Sport Coat Blazer Button Set. SINGLE BREASTED set includes three larger 7/8" buttons for the front closure of the blazer and eight smaller 5/8" buttons for the sleeve cuffs. DOUBLE BREASTED set includes (6) Six larger 7/8" buttons for the front closure of the blazer and eight smaller 5/8" buttons for the sleeve cuffs.