Tubular bells, also called orchestral bells or orchestral chimes, are tuned percussion instruments that consist of a series of 12 to 18 seamless brass tubes suspended from a steel frame and arranged in a piano keyboard layout, with one row for the 'white keys' and another for the 'black keys.' When struck with a mallet, the tubes produce a sound resembling that of church bells, although their tone is clearer and they can attain a greater rhythmic precision. The tubes range in diameter from 1 to 2.5 inches in diameter and from 4 to 6 feet in length, with the greater the length of tube the lower the pitch. The range usually extends one and a half octaves upward from the C above middle C.