The idea comes from stormdrane blog (http://stormdrane.blogspot.it/2011/08/paracord-carabiner-spool.html).
I need something little and heavy that can carry on a rope and a signal tube for diving. So when i found the project on blog i bought a big carabiner from amazon and i created the 2 parts.
I put together with a cable tie (http://en.wikipedia.org/wiki/Cable_tie).
The exact dimensione are on the image
The diameter is 0,12 cm.