BoxGuide is a lightweight, quiet & simple design that works with most aftermarket cranks & frames.It’s composed of an AL-7075-T6 upper plate & a heat-treated cromolylower plate. An adjustable composite upper guide & a polyurethane cartridge-bearing lower roller keep your drivetrain running smooth & quiet. It has a clean hex bolt setup with adjustable plate angles. ISCG & BB-mounted versions available.