Feature: 1. Package included: 1 front hub, 1 rear hub. 2. With 36 hole drillings, compatible with 5/6/7/8S rotary freewheel. 3. Precision-machined steel bearings for a smooth and quick ride. 4. Low-friction seals effectively shut out water, mud and dirt. 5. Internal grease sleeve helps maintain and increase service life of hubs. 6. Aluminum alloy hub shells for easy maintenance and long time last. Specification: This kind of bicycle accessories can help to keep away soil, water and so on, keep the bicycle riding smoothly, and improve the riding safety and comfort. Features: It can effectively block mud and water and reduce loss. Aluminum alloy production, high strength, long service life. With 36 hole drillings, compatible with 5/6/7/8S rotary freewheel. Wear resistant, not easy to rust. With quick removal, easy installation, simple, suitable for a variety of models. Specifications: Material: aluminum alloy Color: black / blue / red (optional) Compatible with: 5 / 6 / 7 / 8S rotary freewheel Front hub length: 100mm / 3.9in Rear hub length: 135mm / 5.3in Weight: 38g / 11.9ounce Package size: 250 * 170 * 50mm / 9.8 * 6.6 * 1.9in Package weight: 727g / 1.6lb Packing list: 1 * Front Hub 1 * Rear Hub 1 * Quick Release Package List: 1 * Front Hub 1 * Rear Hub 1 * Quick Release