Banks SpeedBrake for 2007 - 2010 Chevy GMC Duramax 6.6L LMM. The Banks SpeedBrake cuts downhill speeds by nearly 80% without using the brake pedal. Saves your wheel brakes, keeping them cool and ready for emergencies. Dramatically reduces brake wear. And saves thousands in brake maintenance! SpeedBrake's patented design lets you select your downhill speed (anywhere from 25-75 mph), and then maintain that speed automatically. It's like having exhaust brake cruise control!