Inter-Changeable cables. These fit all the points, Aluminium, Spectra Flair as well as Symphonie.They come with end caps and tightening tool to ensure ends don't come off. 
 These cables come in sizes from 40cm - 150cm, but they can also be joined together with the joining kit (sold seperately) to make the cables longer as you need them
They also fit onto the Knitpro Afghan Crochet hooks
Totally brilliant concept!