BOX revolutionized the drivetrain market by launching their wide-range 9-speed drivetrains. The Prime 9 derailleurs are crafted for 11 - 50t cassettes, sparing you the hassle of adjusting 12 gears. The Box Three Prime 9 rear derailleur is Box's budget - friendly Prime 9 option. It comes with a non - adjustable clutch, bearing pulleys, and a price that won't break the bank. **Who's this item for**: It's perfect for those already using a Box Prime 9 - speed drivetrain or anyone looking to upgrade to Box's innovative wide - range 9 - speed system. **Number of gears**: This is a 9 - speed derailleur. **Weight**: 349g. **Materials**: Made from aluminium, glass fibre/nylon composite, and steel with a sleek matte black finish. **Chain and cassette compatibility**: Designed to work seamlessly with other Box Three Prime 9 drivetrain components, it also performs superbly with any Box Prime 9 parts. **Max cassette range**: - Minimum sprocket size: 11T - Maximum sprocket size: 50T - Total capacity: 39T **Clutch style**: It uses the non - adjustable version of the Tri - pack limited - slip clutch. **Cage length**: Features stamped steel inner and outer long cages to handle wide - range cassettes. **Pros**: Offers great value from Box. It's one of the more affordable rear derailleurs on the market that can handle wide - range cassettes. **Cons**: Has a non - adjustable clutch.

Using the Box Three Prime 9 rear derailleur is quite straightforward. If you're already running a Box Prime 9 - speed drivetrain, simply install it in place of your old derailleur. If you're upgrading, make sure to pair it with other Box Prime 9 components for the best performance. When installing, ensure that the derailleur is properly aligned with the cassette. The long cage is designed to handle a wide - range cassette, so you don't have to worry about chain tension too much. As for maintenance, regularly clean the derailleur to remove dirt and grime. You can use a mild detergent and a soft brush. Check the bearing pulleys for smooth rotation. If they seem stiff, it might be time to replace them. The non - adjustable clutch doesn't require you to make any adjustments, but it's a good idea to inspect it occasionally for any signs of wear. Keep in mind that since it has a non - adjustable clutch, it may not be suitable for riders who need very precise control over the clutch. Also, when choosing a cassette, stick to the recommended range of 11 - 50T to ensure optimal performance.