... ,construction, mining Material: ABS, PE, PP, HDPE is availableColor: red, blue, yellow, white, black, orange is okRib: one rib, two ... ribs and three ribs on the top of shell could be doneLock type of back hoop: Turning knob ... , Yellow, WhiteSize52-60CMFeatures· Safety helmet with a versatile new shell design of V rib with 6 cooling vents on top ... Helmet with 6 cooling vents on top of the shell