Shimano RD-M360 Acera rear derailleur SGS silver. Acera mountain bike rear derailleur with light action operation & over-size pulleys for a wide gear choice Oversize 13-tooth tension & guide pulleys to reduce noise & wear Extension spring & low-friction fluorine-coated link pivot bushing result in a light shifting action Top normal spring for use with Rapidfire shifters IG & HG chain, 7- & 8-speed compatible For use with 28 to 34 tooth low rear sprockets, total capacity 43 teeth