The bass drum is the largest and deepest-sounding member of the drum family. Bass drums are usually cylindrical, with a diameter substantially greater than their thickness, and have calfskin or plastic drumheads at each end of the cylinder whose tension can usually be adjusted with threaded taps or strings. A variety of sizes are available, with the size affecting both the timbre and the pitch. The drums are usually struck with a pair of large, felt-headed sticks, but, depending on the desired effect, can also be struck with percussion mallets, other percussion objects, or even with the hand or fingers.