Teeth made of high-strength steel, for an extra long service life. Aluminum center section, reduces unsprung masses. Permanently joined together with high-strength rivets. At least three times longer service life than other aluminum rear sprockets. 50% lighter than steel rear sprockets. Longer service life of the entire drivetrain kit 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. 2K sprockets are exclusively produced for KTM by Supersprox. This product is protected under the following patents in Europe and USA. EU patent # EP1573234. US Patent # 7.481.729. Patent owner supersprox a.s.