Our Edge Inserts allow the artist to change a variety of different characteristics with each dimension. The E Value changes color, tone, focus, breathiness, pressure, dynamic range, and flexibility. This alters the size of the window opening by the distance from the flue exit to the cutting edge. The L Value changes color, tone, focus, breathiness, pressure, and definition. This alters the length of the cutting edge face, creating a sharper or more blunt angle. The AF changes color, pressure, focus, and definition. This changes the underside face of the cutting edge by adding a cavity below the cutting edge. This changes how fast the air oscillation initiates and stabilizes. E5.5: Darker color, pure tone, compact focus, less breathiness, increased resistant pressure, and with narrower dynamic range and less flexibility. *E6.0: Well-rounded, balanced tone, pressure and playability. E6.5: Brighter color, complex tone, diffused focus, increased breathiness, free-blowing pressure, and with wider dynamic range and more flexibility. L10: Darker color, pure tone, compact focus, decreased breathiness, resistant pressure, and articulate definition. *L15: Well-rounded, balanced color, pressure, and tone. *None (AF): Standard instrument design. AF: Greater increase in clear focus and articulate definition, and with brighter color, free-blowing pressure. View Edge Characteristics Chart Here Terms and Conditions: Shipping, Returns, Cancellation, Warranty * = Included with a RolBec Flute purchase