Authentic. New with tags and in bag. This style was made before 2024 and does not come with the CERTILOGO and will have less of a chance to pass certain authentication apps/services. Is 100% authentic but please research if you plan to resell. Generally run 1 size oversized. Here are the approximate measurements for each available size. Size XXS Length 28” Chest 21” Size XS Length 28” Chest 22” Size S Length 30” Chest 23” Size M Length 31” Chest 24” Size L Length 31” Chest 25” Size XXL Length 32” Chest 26”