Helm Air 27.5 = 170mm - 100mm

Helm Coil 27.5, Helm Coil 29 and Helm Air 29 = 160mm - 100mm

HELM Works Series = 130mm - 100mm 

Helm Forks are travel adjustable, but are optimized for travel settings between 170mm and 130mm of travel (HELM Works Series are optimized 130mm - 120mm). 

Helm Air forks use travel spacers to adjust travel.  Two 10mm travel spacers are included with every Helm Air fork.  Helm Coil forks are adjusted by changing the location of the spring perch (coil piston) on the travel-indexed compression rod. This procedure requires no additional parts.