In general, safety helmets are made of strong plastic material (thermoplastic polycarbonate) or strengthened material (fiberglass) or metal (aluminium or light alloys).

  • 一般情况下,安全帽由高强塑料(热塑聚碳酸酯)或强化材料(玻璃纤维)或金属(铝或轻质合金)制成。
目录 查词历史