Paul Components Melvin Chain Tensioner Single-Speed Time Want to build a single-speed without having to buy a dedicated frame? You can always use a Melvin. The Paul Components Melvin Chain Tensioner Converts frames for single-speed use. The Melvin bolts to the frame where the rear derailleur would go and allows the use of a single-speed rear wheel on bikes with vertical dropouts. Item Specifications Color Black Chain Compatibility Most Narrow 6 Through 9-Speed Chains | Paul Components | Component Melvin Chaintensioner Black