Copper Pipe Type M Hard Tubing.
Mueller
EIS-12M10 1/2" 10feet 0.028wall size
EIS-12M20 1/2" 20feet 0.028wall size
EIS-34M10 3/4" 10feet 0.032wall size
EIS-34M20 3/4" 20feet 0.032wall size
EIS-1M10 1" 10feet 0.035wall size
EIS-1M20 1" 20feet 0.035wall size
EIS-114M20 1-1/4" 20feet 0.042wall size
EIS-112M20 1-1/2' 20feet 0.049wall size
EIS-2M20 2" 20feet 0.058wall size