I have just started training mine twice per week on the Nautilus neck machine at my gym. 4-way, no adjustment required once you set your resistance and seat height. I am measuring at 16.5" right now relaxed, about in line with my arms and calves like others above said. Anyone want to buy my Ironmind neck harness for cheap? I just don't use it any more because this neck machine is a one stop shop and I already have a ton of stuff in my gym bag.