【Compatible with Shimano HG Cassette Sprockets】Supports 7-speed to 11-speed cassette sprockets. This is a basic tool set necessary for replacing and cleaning bicycle sprockets. I purchased this for maintaining my bike, but I never used it and have been storing it. It's new and unused, but the package was opened upon purchase. The following is a product description from the sales site: 【2-Piece Set for Increased Work Efficiency】 A set of a freewheel remover to remove the lock ring and a tuner (holder) to secure the sprocket, allowing for safe and efficient work. 【High Precision and Secure Fit】 The remover is precisely molded to fit perfectly with the lock ring, and the tuner supports stable maintenance with a chain entanglement prevention design. 【Ideal for Home Maintenance】 Easy to handle for bicycle maintenance beginners and DIY riders, allowing you to replace and clean sprockets at home. ・Made in Taiwan 【Notes and Warranty】 This product is not compatible with boss-free type sprockets (sprockets with model numbers starting with MF) such as those found on mama-chari bikes and cross bikes. Do not apply force to the tool with the chain. It is sufficient to simply hold it to prevent it from spinning.