The Box Four Rear Derailleur is the base of Prime 9 Technology that offers an affordable clutch based 1 by 8-speed derailleur that is simple and light; this makes it a perfect candidate for every entry-level bike that traditionally has a 3 by drive-train that is neither durable nor user friendly.

The Box One Prime 9 Rear Derailleur takes the advantages of our legacy 9-speed drive-train but adds the advancements of a modern 1 by; a fully adjustable Tri-Pack Clutch, and an x-wide cage optimized for an 11-50T cassette. Forged construction steps up the durability and performance to an unparalleled level. Suited for the most demanding terrain.

The Campagnolo EKAR Rear Derailleur is designed for the 1x13-speed EKARndrivetrain with a gravel-orientated performance & build. - 2D parallelogram trajectory offers precise mechanical movement for 13 sprockets - High grade polymer pulley wheels (12T upper, 14T lower) allow for smooth chain running and secure retention - Carbon fiber-reinforced polyamide and anodized 7075 and 6082 alloys are lightweight, strong, and durable - Stainless steel bolts for strength and long-term resilience on gravel - Includes clutch lock for easy wheel removal Specifications: - Largest Cog: 44 - Rear Derailleur Mount Type: 10x1 Standard - Chain Wrap Capacity (teeth): 34 - Cage Length: Medium - Rear Der/Shifter Compatibility: Campy EKAR - Drivetrain Speeds: 13 - Weight: 275g

The Campagnolo Super Record EPS 12 speed rear derailleur offers improved shifting performance with a trajectory curve that is optimized for 11-29 and 11-32 cassettes. - Using 3D Embrace technology the inner mechanism embraces more teeth per sprocket thanks to the advanced position of the upper pulley - The 12-tooth pulley wheels allow for the integration of larger cassette range while keeping chain length the same - Upper body adjustments allow you to set the perfect position whether you're riding an 11-29 or 11-32 tooth cassette - An upper body return spring absorbs the energy of any bumps, preserving the hanger, and bringing the derailleur back to position - An aluminum upper body provides high resistance to impacts and greater stiffness - The lower part of the body is made of ultra-light technopolymer, reinforced with long carbon fibers Specifications: - Largest Cog: 32 - Rear Derailleur Mount Type: 10x1 Standard - Chain Wrap Capacity (teeth): 37 - Cage Length: Medium - Rear Der/Shifter Compatibility: Campy Record/Super Record EPS - Drivetrain Speeds: 12 - Weight: 234g

M21 rear derailleurs are designed to work with 6- and 7-speed Shimano road and mountain shifters. Enjoy the wide variety of bikes you can get going again with M21 rear derailleurs. - Robust composite and steel construction - Compatible with Shimano 6- and 7-speed mountain and road systems - Long cage for double or triple cranksets and 32T max cassette cog - Includes frame hanger attachment for use with older frame designs

M21 rear derailleurs are designed to work with 6- and 7-speed Shimano road and mountain shifters. Enjoy the wide variety of bikes you can get going again with M21 rear derailleurs. - Robust composite and steel construction - Compatible with Shimano 6- and 7-speed mountain and road systems

M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. These legendary M26 rear derailleurs put cyclists of all ages back on their saddles with as little frustration as possible. - Robust composite and steel construction - Compatible with Shimano 7, 8, and 9-speed mountain and road systems

R-series rear derailleurs are designed to work with 8 and 9-speed Shimano-compatible road shifters. These R8 rear derailleurs have composite and steel parts that weigh more but have the same durability and performance as R9 and R10 derailleurs. - Steel pulley cage for extra durability - Not compatible with Shimano Tiagra 4700 road system - Short cage for double crankset and 28T max cog - Long cage for triple crankset and 28T max cog

M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. Marvo LT rear derailleurs are built with precision rigid aluminum construction. Let these miracle workers get any bike rolling again. - Lightweight aluminum construction - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 7, 8, and 9-speed mountain and road systems

Not everyone needs the added chain retention provided by our innovative SpringLock system. For those riders, we offer a non-clutch version of our Acolyte derailleur. While still capable of handling a 12-46T cassette, the rear derailleur is the perfect choice for commuter or touring bikes that can benefit from using a wide range 1x gearing system. - Direct path cable routing for smooth and responsive shifting - Compatible with 12-42T and 12-46T 9-speed cassettes - Compatible with Acolyte shifters only

R-series rear derailleurs are designed to work with Shimano-compatible road shifters. These R9 rear derailleurs combine compatibility, weight savings, and a robust design. - Weight-saving aluminum bracket body and outer link - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 9 and 10-speed road systems - Not compatible with Shimano Tiagra 4700 road system - Short cage for double crankset 28T max cog setup - Medium cage for double crankset and 34T max cog - Long cage for triple crankset and 28T max cog

The Sword Black wide range 1x rear derailleur is compatible with both Sword and Sword Black shifters, making it easy to upgrade or mix and match. With capacity for an 11-48t cassette, this derailleur gives you the gear range you need to ride where you want. - Compatible with Sword and Sword Black shifters, as well as Advent and Advent X - Compatible with 9 or 10-speed - Medium cage is crafted with durable steel - 37t capacity

The Sword Black wide range 2x rear derailleur is compatible with both Sword and Sword Black shifters, making it easy to upgrade or mix and match. With capacity for an 11-38t cassette and a 17t chainring gap in the front, this derailleur gives you the gear range you need to ride where you want. - Compatible with Sword and Sword Black shifters, as well as Advent and Advent X - Compatible with 9 or 10-speed - Medium cage is crafted with durable steel - 44t capacity

XLE Rear Derailleur for 10-speed Shimano drivetrains - For MEGA Sprockets w/large cog size 36-42T - Compatible with single, double, or triple cranksets - Total Capacity: 47T

Not everyone needs the added chain retention of a clutch derailleur. For those riders, we offer a non-clutch version of our innovative ADVENT derailleur. Without the clutch in the system, the shifting effort at the lever is reduced. While still capable of handling an 11-42T cassette, the rear derailleur is the perfect choice for commuter or touring bikes that can benefit from using a wide-range gearing system. - Direct cable routing for smooth and responsive shifting - No clutch for ultra-smooth shifting - Compatible with 11-42T 9-speed cassettes - Compatible with ADVENT shifters only

Designed with the rider in mind, the ADVENT rear derailleur packs trail-ready features into an attainable wide-range drivetrain system. The derailleur kinematics are precisely tuned to use a more direct cable path, making the shifting feel consistent across the lowest and highest gears, and everything in between. - Clutch provides stronger chain management over rough terrain - Ratchet-and-pawl clutch is easily adjustable and repairable - Direct cable routing for smooth, responsive shifting - Compatible with 11-42T 9-speed cassettes - Compatible with ADVENT shifters only

With a race-worthy weight and the right gearing for any situation, microSHIFT's top-of-the-line ADVENT X rear derailleur delivers high-end performance without high-end headaches. By using a 10-speed chain and wide range 11-48T cassette with predictable, evenly spaced gear steps, ADVENT X allows you to find the right gear even in challenging conditions. Add in microSHIFT's proprietary ratchet-and-pawl clutch, larger pulleys with taller teeth for better chain retention, and metric adjustment hardware, and you've got everything you want and nothing you don't. - Compatible with ADVENT X 10-speed drivetrains only - Compatible with standard 10-speed chains - Ratchet-and-pawl clutch provides chain security and can be turned on and off with a switch - Metric adjustment hardware - Larger pulley and taller teeth for better chain security and higher ride height

The microSHIFT Sword rear derailleur for 1x system features a modern and innovative design with elegant mechanical operation. The cage is designed to use with a single chainring and an 11-48t cassette, giving you a wide range and excellent climbing gears. Not only that, but the cage itself is replaceable, so you can repair a damaged cage or even switch to the 2x cage easily. It also features a hidden clutch design with instant engagement and silent operation to keep the chain secure over rough terrain. With the introduction of Igus bushings on the parallelogram, lateral stiffness and longevity are both improved, making shifting snappier and more robust. Even the barrel adjuster is innovative, with an orbital housing stop that rotates by 15 degrees to reduce cable friction from tight housing bends. - Compatible with Sword and Advent X shifters - Compatible with standard 10-speed chains - Silent clutch with instant engagement and integrated switch - Igus bushings for added stiffness - Replaceable cage - Max cassette range of 48t - Orbital barrel adjuster reduces housing bends for less cable friction

The microSHIFT Sword rear derailleur for 2x system features a modern and innovative design with elegant mechanical operation. The cage is designed to use with a double chainring and an 11-38t cassette, giving you a very wide range with excellent climbing gears. Not only that, but the cage itself is replaceable, so you can repair a damaged cage or even switch to the 1x cage easily. It also features a hidden clutch design with instant engagement and silent operation to keep the chain secure over rough terrain. With the introduction of Igus bushings on the parallelogram, lateral stiffness and longevity are both improved, making shifting snappier and more robust. Even the barrel adjuster is innovative, with an orbital housing stop that rotates by 15 degrees to reduce cable friction from tight housing bends. - Compatible with Sword and Advent X shifters - Compatible with standard 10-speed chains - Silent clutch with instant engagement and integrated switch - Igus bushings for added stiffness - Replaceable cage - Max cassette range of 38t - Orbital barrel adjuster reduces housing bends for less cable friction

Paul Components Melvin Chain Tensioner. Converts frames for single speed use. Long enough for a Dingle-setup, (2 rings, one cog) 20T max. - The Melvin uses two pulleys, just like a rear derailleur, which gives it 20 teeth of chain wrap - Will work with multiple front chain rings while maintaining proper chain tension - The pulleys are made of extruded and machined aluminum and have sealed bearings for durability - Pulleys are 2.25mm thick at the tooth which fits inside most narrow 6 through 9 speed chains, and the pulley cage is wide enough to allow 1/8? single speed chains as well - Long enough for a Dingle-setup, (2 rings, one cog) 20T max - Do not use with a coaster brake or fixed gear - Includes Paul's own Sealed Bearing Pulleys

SRAM's X3 Rear Derailleur is ready for adventure. Its composite and steel construction is tough, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts. This derailleur is compatible with 7- or 8-speed drivetrains.

SRAM's X4 Rear Derailleur provides precise, dependable shifting along with long-term durability. Its aluminum and steel construction delivers through the roughest trail, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts. This derailleur is compatible with 7- or 8-speed drivetrains.

SRAM's X5 9-Speed Rear Derailleur provides precise, dependable shifting along with long-term durability. Its aluminum construction keeps the weight down, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts.

SRAM's X5 10-Speed Rear Derailleur provides precise, dependable shifting along with long-term durability. Its aluminum construction keeps the weight down, while SRAM's 1:1 actuation ratio and direct cable routing provide quick, reliable shifts.

Incredibly fast, astonishingly quiet, and impressively precise—fly through all 11 gears with SRAM's Rival 22 Rear Derailleur. It takes advantage of SRAM's Exact Actuation technology for precision shifts every time. Carefully shaped jockey wheels work together with the sculpted chain pulley cage for lightning-fast, ultra-precise shifts, and an elastomer coating applied to the jockey wheels makes for extra quiet operation. Aluminum inner and outer cages, aluminum links, and stainless steel hardware keep the durable Rival 22 at a svelte 180 grams.

SRAM's GX 2x10 rear derailleur provides incredible shifting speed and precision. Exact Actuation technology eliminates slop and shifting variation. Roller Bearing Clutch technology delivers maximum drivetrain stability—even through the most punishing terrain. And with Cage Lock technology, wheel removal and installation are easier than ever.

Incredibly fast, astonishingly quiet and impressively precise—fly through all 11 gears with SRAM's Rival 22 Rear Derailleur. It takes advantage of SRAM's Exact Actuation technology for precision shifts every time. Carefully shaped jockey wheels work together with the sculpted chain pulley cage for lightning-fast, ultra-precise shifts, and an elastomer coating applied to the jockey wheels makes for extra quiet operation. Aluminum inner and outer cages, aluminum links, and stainless steel hardware keep the durable Rival 22 at a svelte 191 grams. Plus, SRAM's WiFLi technology delivers a wider range of gears than your standard triple, faster shifts through two chainrings and every gear on the rear cassette, all with significant weight savings.

The SRAM NX X-HORIZON rear derailleur provides the same smooth, reliable shifting action as XX1—from the larger upper pulley offset to the 12-tooth X-SYNC pulley wheels. By eliminating unwanted chain movement, X-HORIZON shifts faster, puts an end to ghost shifting and reduces shift force and chain slap. And with Cage Lock technology, wheel removal and installation are easier than ever. - X-HORIZON design that reduces shift force, ghost shifting and chain slap - 12-tooth X-SYNC pulley wheels - Fully compatible with all SRAM MTB 1x drivetrains - Most affordable fully featured 1x rear derailleur in the industry - Speeds: 11-speed - Weight: 322 grams - Color: Black - Compatibility: X-ACTUATION - Bearings: Steel - Cage Size: Long - Max Tooth: 42

This new SX Eagle derailleur is your entry point to the SRAM Eagle Ecosystem. Sharing many features with the rest of the Eagle Ecosystem like the proven SRAM 1x-specific X-HORIZON body design, it can accommodate both 11-50T and 10-50T cassettes. The SX Eagle is cross compatible with much of the Eagle Ecosystem, making it easy to personalize and upgrade your ride when you are ready. - A full featured Eagle derailleur, compatible with the Eagle Colorsystem - X-SYNC pulley technology provides greater efficiency, crisper shifting, and quieter operation - Cage Lock offers discovery-level riders easy wheel removal - 50T max rear cog - Battery Not Included

SRAM's XX1 Ceramic Bearing Rear Derailleur Pulleys run on super-smooth, efficient ceramic bearings so your drivetrain rolls with ease. They are lighter than conventional pulleys and even come with SRAM's ceramic-bearing grease in an easy-to-use 10ml syringe.