... rib, two ribs and three ribs on the top of shell could be done Lock type of back hoop: Turning knob (rachet), Press button ... on top of the shellMaterialShell-ABSWeight380gAccessoriesFabric tape, buckle, pinlock, ratchetColourRed, Yellow, WhiteSize52-60CMFeatures· Safety helmet with a versatile new shell design of V rib ...