This 12mm bung plugs the hole in the head pipe when you remove the O2 sensor from the headpipe on the 2020-21  EXCF/XCFW/FE and FE-S model bikes.  You have to use the O2 sensor eliminator we have, to use this plug.  It doesn't enter into the pipe body, so it doesn't hurt flow

 

THIS ONLY FITS ON USA AND CANADA SPEC BIKES

12mm O2 sensor bung plug (block off)

$14.99Price