Copper-aluminum connecting pipe & air conditioner parts 1)Copper tube:OD:1/4,&3/8,&1/2,& ... ,4,6,7,10, Copper-aluminum connecting pipe & air conditioner parts(1)OD:1/4,&3/8,&1/2,&5/8 ... tube design is 1.5 times the wall thickness, not only to ensure strength and relative connecting copper pipe is easier ...