Product Details Standard Pro-1 Head fits SDM or RDM 2-Pin stainless steel vertical slide collars New 50cm tail is stiffer and creates modern, straighter bend New loop-n-go outhaul block for quick, centered sail position Built-in excess rope retention Harness line index markings Absolute boom length markings This baby is skinny! Range: 135-185cm, Grip Diameter: 24.5mm – 1 3/32\