Aluminum alloy CNC machined lightweight tensioner arms, derailleur, fixture, and thumb shifter.
Compatible with A/C Line Mk 5 and older models (P/T Line version is in other listings). Comes with X7 advanced Cog Set on stock wheelset for 5-speed 11-25T (#X5AdvancedCogSet).
The largest cog is 25T (vs. the original max 15T on A/C Line).