The size of the mouth (length, width and depth) is usually in proportion to the instrument's bore, depending on the model of instrument and specifically which original instrument is being copied (in the cases of recorders). Many mass-produced factory instruments feature a voicing of a rectangular or flat lozenge cross section. Such a flat and rectangular voicing however, produces a less-than-sweet tone and offers far less dynamic flexibility (pitch bending) than a flute embouchure. The recorder voicing was designed to limit pitch bending for a more stable tone with variations in breath pressure. Typically, a shallow ramp instrument, such as a tabor pipe, will allow faster register changes, pitch bending and "flutey" tone, while an instrument with a deeper ramp will limit fast register changes, pitch bending and produce a more "reedy" tone.