The Tremolo effect, not be confused with Fender's vibrato bridge, electronically adjusts the amplitude (volume) of the instrument. Many tremolos offer a couple of different wave forms (square or curved) that vary the sound of the tremolo from a staccato to a slower change. It is a very dramatic effect when used correctly. Early examples include "Mona" by Bo Diddley and "Crimson and Clover" by Tommy James and the Shondells. A more recent example is heard on Green Day's "Boulevard of Broken Dreams".