1. Large Capacity: With A Capacity Of 30 Liters, You Can Hold Some Carry-On Luggage And Spare Items Without Being Carried On Your Shoulders. This Will Reduce The Pressure On Your Shoulders And Meet All Long-Distance Travel Requirements. 2. Waterproof: It Is Made Of High Quality Waterproof Nylon Fabric, Which Is Difficult To Penetrate When It Rains And Has Good Workmanship. It Is Very Durable, Waterproof, Tear-Resistant And The Reflective Logo Can Increase The Safety Factor When Driving Outdoors. Can Perfectly Protect Your Things. 3. Perfect Design: The Trapezoidal Design Can Prevent The Back Heel From Rubbing On The Backpack While Driving. There Are Buckles On The Front And Back Of The Bike Seat Bag And Buckles On The Left And Right Sides To Ensure A Firm Fixation. 4. Multifunction: The Main Pocket Is Equipped With A Double Zipper And Offers Space For Items. There Are 4 Expansion Bags And 2 Mesh Pockets On Each Side. You Can Store Frequently Used Items. The Rear Highlight Reflector Can Remind You Of Late-Night Vehicles.If You Drive At Night, Ensure Safety. 5. Wide Application: It Is Suitable For All Types Of Bicycles With Rear Seats, Such As: B. Mountain Bikes, Racing Bikes, Etc., And Also For Most Bicycle Frames. It Is The First Choice For Long Distance Riders.