Giro created the bishop xl mtb helmet for riders in search of the classic giro fit but in need of an extra large size inspired by the sleek lines and serious ventilation of our reveltrade and veronatrade this helmet is equally at home on pavement and dirt and its in mold construction keeps it light without compromising durability the on the fly adjustable acu dialtrade system makes it easy to custom tune the fit for maximum comfort and stability the original acu dialtrade system co