Xlab carbon sonic rear mount system after the successful and very popular sonic wing many triathletes and dealers asked when we were going to bring out a carbon version we were already working on it but we wanted it to be the very best in the world by the worlds best we mean the lightest the most positions the most customizable with options best engineered and tested and of course the fastest you wont want to be seen without it because without it you wont be seen worlds most versa