purchased some 6 feet long 5/8 inch thick rubber coated steel cables with built in locks from Lowes, Walmart or Advance Auto Parts. They are made by Brinks or Masterlock
Brinks makes good stuff.
I have a heavy duty "padlock" by Brinks.
I tried to get extra keys made...you cannot do it. Brinks can though...maybe a locksmith could, but Joe at the local hardware dept cannot.