The Sram Force 1 rear derailleur features all the technology of the Sram 1x mountain bike, providing the fastest and quietest 1x11 shifting available. Sram 's unique clutch system eliminates chain slack, providing smoother, quieter and safer chain travel.A specially designed X1 rear derailleurExact Actuation™ for fast, precise shifting using Sram 's 1:1 activation ratio (shifter cable travel: derailleur movement). Compatible with 10 and 11 speeds.The X-Sync™ sprocket benefits from a 12-tooth design that helps control the lateral movement of the chain.The X-Horizon™ "straight parallelogram" design limits all movement to a horizontal axis to prevent unintended shifting and reduce shifting force.The one-way Roller Bearing Clutch™ controls chain tension for smooth shifting.Cage Lock™ technology allows for faster wheel changes and chain installation.10 and 11v compatibleCog: AluminumRollers: 12-tooth, cartridge bearingHardware: stainless steelWeight: 261grCompatible with Sram E......