Designed for machines with larger tires. Helps restore power loss due to addition of larger tires. Allows for easier turning of larger tires in the mud. Better low end power and torque. Quicker backshift which results in crisp throttle response. Reduces belt slip and clutch heat. This item fits H-D the following vehicle applications: fits KAW KVF650 Brute Force 4x4 2005-2011 fits KAW KVF650 Prairie 4x4 2002-2003