Copper to copper to copper. Sweat/solder fitting.
GV1359 INCREASER,GLV 6X7$11.99
16509 WRAP,PIPE 1X3X25FT$9.29
1 9/16 - 2 1/2CLAMP$3.19
6206053 CLAMP,MINI 5/16-7/8"$1.79