All sizes given are subject to manufacturing tolerances (+/- 2%). Men's a.b.Extra Small70cm48cmSmall72cm51cmMedium75cm53cmLarge78cm55cmExtra Large81cm57cmXXL84cm59cm3XL88cm61cm4XL91cm64cm5XL95cm66cm Kids' Sizea.b.4 Years48cm36cm6 Years52cm38cm8 Years56cm40cm10 Years60cm42cm12 Years64cm44cm14 Years68cm46cm