This is a cassette brush - the hook end is super handy for raking gunk out of your cassette and also pretty handy for that same job elsewhere on your drive train. Use the brush end for varying levels of scrubbing action on and around your cassette and drive train. The exact technique you go with doesn't have to be pretty - Just get in there and get it clean. Use our Dirt Juice cleaners for help loosening and breaking up the crud if required.
