250 feet of seven strand bare copper wire.
I use a lot of copper: copper pipe for chimes, heavy copper wire for hooks and loops and hanging stones, and slightly lighter copper wire for wrapping glass. I go through a spool as pictured above about every six months.
These spools hold 250 feet of seven strand, and I unwrap the strands giving me a total of 1750 feet.
I calculate over my wire wrapping career, I've wrapped well over 9 miles of wire!
You can see what I do with all this wire by visiting my website: Coast Chimes.