First Degree NEPTUNE Challenge AR Owner's Manual page 8

Fine Tuning the Neptune Challenge:
pre-stressed frame . Using the mid-leg as your guideline, tighten the vertical frame tensioning bolt until
the mid leg rises approximately 3-5mm off the floor. The mid leg should just touch the ground during a
rowing stroke.
Adjust Vertical seat rail bolt here
using the Allen Key here:
And with the multitool
here:
The Neptune Challenge is designed to function as a
Mid leg
3-5mm off the
floor is ideal