Arabic qanuns are usually constructed with five skin insets that support a single long bridge resting on five arching pillars, whereas the somewhat smaller Turkish qanuns are based on just four. This allows Arabic variants of the instrument to have more room for the installation of extreme bass and treble strings. Kanuns manufactured in Turkey generally feature 26 courses of strings, with three strings per course in the case of all regional variants. Contemporary Arabic designs use Nylon or PVC strings that are stretched over the bridge poised on fish-skins as described on one end, and attached to wooden tuning pegs at the other end.