This motorcycle tail bag select and thicken waterproof fabric, rain proof and wear-resistant, and give a dust-proof cover, double waterproof travel without worry. Highly reflective strips are installed on both sides to enhance the safety of night and haze travel. Expandable for a larger volumes for holding helmet. There is no doubt it's a nice helper for motorcycle riding. Features: Premium Material - Motorcycle bag is made of 1680D Oxford cloth + waterproof cloth +EVA. External 1680D Oxford cloth tear resistance to provide perfect durability and long life. Waterproof material and rain cover you can use it on rainy day. Linner with oxford cloth soft and breathable. Reflective Design - Reflective straps on the front of backpack for safe riding at night, expandable for a larger volumes for holding helmet. Two-way zipper design, easy to take items from all angles. Practicality And Versatility - A Classic Appearance and all the features you could ever want. A nice item to store your helmet, wallet, phone, camera, energy drinks, etc. Also features a expandable bottom section to enlarge storage space. It's also a decoration to your motorcycle with modern design. Large Capacity. Multifunctional Usage - The motorcycle backpack fits most of the motorcycle, dirt bike, dual sport and enduro, it can also be used as handbag,shoulder bag and messenger bags. Specifications: Material: thickened water repellent Oxford cloth + carbon fiber pattern Capacity: 30L-40L Size (approx.): Before expand: 360 * 270 * 230mm / 14.2 * 10.6 * 9.1in After expand: 360 * 310 * 270mm / 14.2 * 12.2 * 10.6in Package size: 360 * 280 * 240mm / 14.2 * 11.0 * 9.4in Package weight: About 1200g / 2.65lb Packing List: 1 * Motorcycle Bag 1 * Waterproof Cover 1 * Backseat Installation Belt 2 * Shoulder Straps