Eccentric design allows the head angle to be changed by 1 to 1.5 degrees and bottom bracket height to lower or raise by shortening or lengthening the effective eye to eye of the shock- Slacken the head angle for steeper courses or steepen it for sprinting- 6mm hardware provides the greatest amount of alteration- Used on World Cup circuit by many of the top riders- Made from Grade 5 titanium, which is significantly lighter than steel hardware- Sets of 2 for 1/2" shock eyelet shocks, see www.burgtec.co.uk/ for frame fitment chart