 The amount of tension a cellist puts on the bow hair depends on the preferences of the player, the style of music being played, and for students, the preferences of their teacher.Bows are also made from other materials, such as carbon-fibre—stronger than wood—and fiberglass (often used to make inexpensive, lower-quality student bows).An average cello bow is long (shorter than a violin or viola bow) high (from the frog to the stick) and wide.