The Foba CIBAL is a combitube extension with non-rotating bolts. Its non-rotating bolts ensure a rock-solid fit, with no variance between the extension and your original Combitube. The starting point of the Foba Combitube system is the tube itself. The Combitube is made of aluminum and has a non-reflective matt black surface. The unique cone connector allows you to connect an unlimited number of Combitubes.