What's not to love about a clean drivetrain? The Park Tool GSC-3 Drivetrain Cleaning Brush is dual-sided and designed for the hard-to-reach parts of bicycle drivetrains. The long and stiff bristles enable you to get into the cracks of cassettes and chainrings while the slim end works to scrape and pick at grime in tight to reach spaces such as between sprockets and on pulley wheels. Features: Drivetrain cleaning brush for hard-to-reach places Long, stiff bristles for cleaning cassettes and chainrings Slim contoured end for scraping in tight spaces