Kids don't think twice about fit systems and tech specs, they just want to go ride! The Giro Rascal's new OneStep fit system provides a simple and intuitive method to quickly send little riders on their way.. . One Step Fit System is simply the fastest and most intuitive way to properly fit a childs helmet. Simply close the pinch free buckle, and theyre ready to go. For added visibility, parents can click on the integrated rear LED taillight. In mold EPS liner for great structural integrity. 12 vents to keep little heads cool. Built in visor. Universal size, fits 19.75 21.5 in..