The famous swordsman Miyamoto Musashi designed and made several tsubas on this general design.  This tsuba is a modern damascus steel spin on one of those designs.  The steel was forged by Walter from 1050 and 15N20 steel for a recently completed YouTube video.  2.75" in diameter; .2" thick.  The tsuba has been salt blued.  (This process that can be applied to any of the tsubas available here, by the way.  Shoot Walter a note here for details!)