SKS Chainblade Black (Max 46-48 Teeth) Derailleur Gears Only:

The innovative, lightweight Chainblade system includes a telescopic function, adaptable to the length of the rear chainstay, + / - 125mm

Constructed from aluminium, plastic and zinc plated high quality steel, in a smart matt black finish, 3 versions are available for different types of gear systems.

Only for derailleur gears, crankset must include a chainguard ring; max chainring diameter 199mm / 46-48 teeth