This mountain bike sealed bearing hub is designed for cross country bicycles. It is compatible with 7-10 speed and features a steel or aluminum tower base with 24, 28, 32, or 36 holes. The hub has sealed bearings for smooth operation and is available in black or red. It supports 7-speed card flywheel with gaskets and can be installed directly with 8/9/10 flywheel. The hub weighs approximately 216g for the front and 419g or 495g for the rear, depending on the tower base material.