Replaces rear derailleur with chain tensioner for a simple, secure drivetrain Expert version elevates the Colab chain tensioner for the most extreme use and easy adjustment Adding 15mm of adjustability for the chainline by loosening one bolt, the Expert version helps 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 Compatible with 9/10/11-speed chains, 13-17 tooth cogs Aluminum construction, made in Germany TECH SPECS Model Colab Expert Chain Tensioner Mount Deraileur Hanger Color Black Weight 162g