The new Shockblade/Shockboard cylinder mounting system (part no. 11776) now works securely on larger steerer tubes. The system covers a diameter of up to 39 mm (1.5 inches) and is made of very strong, glass fibre reinforced plastic. It is an expanding cylinder. The more you tighten the lower screw, the more it expands and presses against the inner wall of the steerer tube. A distinct cracking noise will be heard during initial assembly and is absolutely normal. There are 2 different cylinder sizes to choose from:
Cylinder 1 19-29 mm
Cylinder 2 29-39 mm
Here is an illustrative animation