The SRAM XX1 Eagle Derailleur has been specifically engineered to accommodate the Eagle drivetrains need for greater capacity, including the brand new 10-52T Eagle cassettes, while still being compatible with older 10-50T cassettes.X-Horizon design offers slick shiftingType-3 roller bearing clutch provides excellent chain retentionRe-engineered mounting system and cage lockDesigned to be used with SRAM Eagle drivetrains Suitable for new Extended Range 10-52T Eagle cassettesThe XX1 Eagle Derailleur features a 14-tooth X-SYNC lower pulley to allow for the 10-52T Extended Range cassette, a type-3 roller bearing clutch for maximum drivetrain stability with reduced derailleur bounce and chain slap, a re-engineered mounting system and a re-positioned cage lock system for easy chain and wheel installation and increased durability. Designed to be used with SRAM Eagle drivetrains and Extended Range cassettes, the XX1 is a fundamental component in the Eagle range.