Monocoque body, custom alloy, fully articulating head, absolute length markings, proven easy to use adjustment collars, positive snap-in skinny adapter, modern bend curve, etc. We put it all in our new 2010 top end aluminum booms, except the price increase. Pro 1 Alloy booms have exceptional torsional rigidity and fit both standard and reduced diameter masts perfectly. The addition of absolute length markings on a generous 62cm tail-piece aid with rigging your sail properly. The rounded curve of the 165 model makes hand transitions during jibes, tacks, and the most advanced freestyle moves feel natural. Range: 165-227cm, Grip Diameter: 29mm - 1 1/8"