XTR Shadow ES 12-speed wired rear derailleur for the ultimate in Ebike shifting performance and durability Precise and clean wired shifting which Integrates with your Steps Ebike system via EW-SD300 wires When connected to your Steps Ebike system Auto shift and Free Shift function can be used Crash recovery function, absorbs impacts and returns to its original position Shadow ES features a super low profile skid plate design and optimized slant angle for optimal clearance Shadow ES uses a dual spring chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shifting The Shadow ES system is also zero maintenance and has no degradation of performance Unique structure using two springs has a tighter chain wrap that improves shifting and security with increased spring force by 70%, allowing the chain to mesh firmly with the sprocket With the tighter chain wrap skipping is prevented even as the cogs wear 13T solid pulleys and decreased derailleur tension prevent high chain tension in low gears Full carbon fibre outer pulley cage saves weight while alloy inner cage increases rigidity Cold forged wide alloy links and pivot body Four fluorine-coated link pin bushings Specifically designed to work with 12-speed HYPERGLIDE drivetrains 10-51 tooth compatible SGS cage