Check the listing for details. Reverse Colab Pro Chain Tensioner - Adjustable CNC Aluminum Drivetrain Upgrade. Color: Gray, Condition: New. Listed at 415.10 USD. Replaces rear derailleur with chain tensioner for a simple, secure drivetrain . Offering a user adjustable clutch system, the Colab Pro allows the rider to fine tune the level of tension on the chain, to give the quietest ride no matter how hard the terrain gets. A simple turn of the central allen bolt offers a huge range of adjustment to suit every bike, suspension and riding style eliminating chain slap . 15mm of adjustability for the chainline by loosening one bolt, helping riders achieve perfect chain alignment without the removal of the tensioner . Adjustable limit stopper as well as a pinch bolt on the mounting bracket and higher spring tension provide more chain retention and also maintains position when the rear wheel is removed . CNC Aluminum pulleys for maximum durability .