This is the Sonic Ergo 35a aerobar. It is designed to help you cheat the wind by allowing you to get into an aerodynamic position. The simplistic clip-on design looks clean and is able to be added to most round bars. Features: Armrest Offset: -70mm to -2.5mm in 7.5mm steps Armrest Width: 124mm to 290mm in 18.5mm steps (With Extensions at 100mm) Armrest Stack: 60mm to 70mm in 5mm increments (With aftermarket Riser Kit) Extension length and rotation can be easily adjusted using the top bolt Specifications: Length: 400mm Clamp: 31.8mm (26.0mm w/ Shims) Material: Aluminum Color: Black Weight: 559g