After passing over the saddle insert, each string makes a slight downward angle toward the stopbar tailpiece, vibrato, or on hollowbody guitars a trapeze tailpiece. Some solid body guitars have "strings through the body" construction. Whichever way the strings are held, the fact that the string makes a downward angle after the saddle creates "break angle". Break angle keeps the string from popping out of the saddle insert's groove because the angle causes the string to sit tightly over the saddle. Break angle also contributes to the guitar's sustain and on an acoustic guitar, its volume. There is also break angle created over the nut caused by the headstock pitching back.