The shaft is typically made from hardwood or bamboo but may also be made from aluminum or carbon fiber. The head can be constructed from a number of different materials, though felt wrapped around a wooden core is the most common. Other core materials include compressed felt, cork, and leather.[16] Unwrapped sticks with heads of wood, felt, flannel, and leather are also common.[2] Wooden sticks are used as a special effect[17]—specifically requested by composers as early as the Romantic era—and in authentic performances of Baroque music.