Material:ABS,PE,PP,HDPE Anti-shock Light weight,Good strength,Good toughness Petroleum, chemical, power ,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 (rachet), Press button and inserting is okLock type of chin band: press ...