The tubular and conical wooden pipes are made on a lathe and tuned with stopped plugs. Larger (lath) pipes are long rectangular tubes made by sticking four thin slats of wood together with glue and carving a whistle for the end. Wooden tubes that can be seen are layered with gold or aluminium paint before tuning. The metal pipes are made from ordinary tubing with whistles hand-carved out of aluminium wedged inside below the flute-slot. These are tuned firstly by their chosen length and more finely by moving the whistle plug up or down the tube. Dummy pipes are also installed on the front of the instrument for decoration. In addition to pipes, a barrel organ may have drums, acoustic woodblocks, reeds, tubular or conical bells, horns, cymbals or other musical instruments.