If you're looking for the ultimate in quality and performance, this sprocket is the one for you! High-strength steel teeth, give long service life. Aluminum inner ring, to reduce unsprung weight. Joined together permanently with high-strength rivets. At least three times longer service life than other aluminum rear sprockets. 50% lighter than a conventional steel rear sprockets. Another benefit: More durable rear sprocket, helps increase the service life for the entire drivetrain. 2K sprockets are exclusively produced for KTM by Supersprox. KTM PowerParts P/N: 584.10.051.051/04.