The Park Tool GSC-3 Drivetrain Cleaning Brush is a dual-sided brush, specifically designed for cleaning hard-to-reach areas of the bicycle drivetrain.The long, stiff bristles of the GSC-3 are narrow enough to reach between the gears of tightly-spaced modern cassettes, while the slim contoured end is capable of picking grit and grime out of tight spaces such as derailleur pulley wheels.
Best Price: £7.99 from Leisure Lakes Bikes