There has been a run on the Kanthal A-1 resistance wire that's been for sale on eBay with the surge in rebuildable atomizers. I've done some research into the resistivity and composition of the various Kanthal and Nichrome wires.
Kanthal is an alloy composed mainly of Iron, Chromium and Aluminum. The main difference between the composition of the different grades of Kanthal is the percentage of Aluminum