The kit consists of a single 20, 23, 25 or 27m 5th line and the Y bridle, the video below explains how to fit the lines and change the kite back to 4 line mode again too.
Amp kites ship standard with 23m lines.
AMP V1 4-Line to 5-Line Conversion (Kite and Control System) from Ozone Kites on Vimeo.