The bell sweep is one of the most popular and winning helmets on both the road and mountain bike circuits the sweep features bells top of the line twin axis gear tag fit system with 20 functional vents actively channelling airflow over the head and out the rear its easy to see why the sweep is a racer favoritebells next generation twin axis gear tag fit system adjusts to the head on two axescircumferentially as standard fit systems do but also horizontally to better accommodate diff