The Shimano Tourney TY300-SGS rear derailleur features SIS Rear Indexing and Double Servo technologies to provide smooth action with perfect tracking for the most accurate SIS shifting.

• SIS Rear Index Shifting System provides smooth action
• Double Servo enables the guide pulley to track the cogs closely while moving front to back, optimizing each shift
• Designed to keep the rear derailleur guide pulley at an optimum distance from each sprocket for accurate SIS shifting
• 13t upper and lower pulleys
• Compatible with HG 6/7/8 speed chains