Normal PVC electrician's tape works, but the tape gradually slides over itself under tension, exposing part of the adhesive, which then picks up fluff and dust and looks messy. Self-fusing tape doesn't do this, because it doesn't have a separate adhesive layer, it sticks to itself and forms a homogeneous band of material around your bar, like a rubber band rather than a plastic/glue Swiss roll.
http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=10549016&fh_location=//catalog01/en_GB/categories%3C%7B9372013%7D/categories%3C%7B9372033%7D/categories%3C%7B9502021%7D/specificationsProductType=tape/specificationsSpecificProductType=adhesive_tape&tmcampid=4&tmad=c&ecamp=cse_go&CAWELAID=396930199
Normal PVC electrician's tape works, but the tape gradually slides over itself under tension, exposing part of the adhesive, which then picks up fluff and dust and looks messy. Self-fusing tape doesn't do this, because it doesn't have a separate adhesive layer, it sticks to itself and forms a homogeneous band of material around your bar, like a rubber band rather than a plastic/glue Swiss roll.