Cooling water tunnel is gun drilled with deep whole driller to achieve good conductivity and cooling performance, and so reducing the power loss in the brasses, for longer working life.

• 冷却水道用深孔钻加工打出。故其导电性能好，冷却效果佳。从而能减少铜瓦上的电能损耗，提高使用寿命。