The Sonic/Ergo/43a aerobar is a great option for any rider looking for a neutral wrist angle and positioning versatility.The 43a is an enhanced version of the popular t3 extension,The Sonic/Ergo platform offers a large range of adjustment in every dimension ÔÇô enabling riders to optimise the comfort of their position,The 43a extension offers a ÔÇÿwrist reliefÔÇÖ style bend that is intended to allow the extension to hug to the arm for improved aerodynamics without sacrificing wrist comfort,Fit range: Armrest Offset -70mm to -17.5mm in 7.5mm steps, Armrest Width 124mm to 290mm in 18.5mm steps, Armrest Stack 60mm, Extension Width 100mm.