Copper-aluminum connecting pipe & air conditioner parts 1)Copper tube:OD:1/4,&3/8,& ... :3,4,6,7,10, Copper-aluminum connecting pipe & air conditioner parts(1)OD:1/4,&3/8,&1/2,&5/8 ... ensure the separation of water and moist air on the corrosion of aluminum tubes, life is more than 20 years. ... of copper is 1.8 times of aluminum, together with the outer layer for corrosion prevention and control cross-linked ...