My head size always seems to fall in-between sizes for most helmet manufacturers. Ordering the next size up usually means the helmet makes me look like a giant mushroom. Not the case with S1. The Lifer design/profile looks great, and the one-size-fits-most approach really works. Using changeable pads to fine-tune the fit is genius, and including the next smallest and largest size at no additional cost is very generous. My helmet fits great, looks great, and I’m very satisfied with this purchase.