Ochain E and N can be upgraded by installing the correct Ochain Upgrade Kit, which includes the 5 position External Travel Adjust knob, Rack, steel insert, spring, washer, bolts, and outboard plate. Installing this kit will make it so that your Ochain will have Lock, 3º, 6º, 9º, and 12º of travel adjustment available on the fly. 

Note: Moving from Ochain E to Ochain S or Ochian N to Ochain R can compromise the compatibility between Ochain and cranks (because of the External Travel Adjust Knob dimension) if the cranks are not a SRAM product.

SKUs
11.6118.083.003 (N to R Upgrade)
11.6118.083.004 (E to S Upgrade)