Bell Muni Bicycle Road Helmet, Hi-Vis Green, Medium/Large Urban/street oriented bicycle helmet with integrated rear lights and rear-view flip mirror Universal-fit for adults with the OneStep Plus Fit System; 54 to 61-centimeter head circumference Durable Fusion in-mold microshell construction Channeled ventilation and integrated rain gutters Blade Visor Plus holds foldaway flip mirror; one year warranty