High Grade: Insulated copper wire that contains a minimum of 75% copper versus insulation
Med Grade: Insulate copper wire that has a minimum of 50% copper versus insulation
Low Grade: Insulated copper wire anything less than 50 % copper versus insulation, such as extension cords, speaker wire, phone line etc.
Bright and Shiny: copper that has been stripped of all insulation, must be thicker than a pencil lead and contain no paint, solder or oxidation.
Copper #1/pipe: Copper Pipe That Is Clean of Any Paint, Solder and Oxidation.
Copper #2: Copper Wire (smaller than a pencil lead) or pipe that contains solder or oxidation etc.
Sheet aluminum: thin, light weight aluminum such as siding, gutters etc
Extrusion: Molded aluminum such as window framing, screen doors etc.
Cast: a heavier quality aluminum that you find more in automotive parts and or kitchen pots and pans. Cast can with hold more heat than other aluminum.