Selle CHROMAG OVERTURE Rails CrMo Noir Rose No Hartje this cassette is designed in Newsoft this cassette is designed in three parts with the first sprocket clusters made from hi ten steel and the last two sprockets of 45 and 50 teeth made from 7075 aluminium to save weight Sizes Chest Circumference Waist Circumference XS 89 94cm 74 79cm S 94 99cm 79 84cm M 99 104cm 84 89cm L 104 109cm 89 94cm XL 109 114cm 94 99cm XXL 114 119cm 99 104cm XXXL 119 124cm 104 109cm Measure your chest circumference by passing the tape measure under your armpits and across the upper part of your chest Kevlar reinforcements ensure greater durability for this saddle the CHROMAG Overture saddle allows better trick execution thanks to its shape