PORTABLE TRIANGLE BAG: Bike triangle bag only 0.35lb, total 1.2L space for daily use. Our designer has try many size standard for this bag to get the largest space and the best adaptability. This large and durable bike storage bag is designed for road, mountain and commute bikes.DURABLE 3 LAYERS SHELL: Bike bag is made of the most durable shell. The outside layer is PU+Polyester, the middle layer is 5mm foam, the inner layer is polyester cloth. Durable material is very suitable for bicycle commuter, travel and daily storage.LARGE STORAGE: Big enough to hold all of your tools and necessary things, small enough to sit under the frame of your bike. Spacious storage pocket to hold your phone, earphones and money clip, while the other big mesh pocket fits your keys, nutrition, and more.STABLE 3 MOUNTS STRUCTURE: Bike frame bag has 3 straps for install on bike tube. This 3 staps are sewing on the bag and can hold bag stable. The triangle bag wont move around even if you are riding on rough roads, and it is very easy to install by straps. The pouch fits for most mountain, road and commute bikes.HUMANIZATION DESIGN: A. Big zippered opening mouth design for easy access. Durable zipper closure. B. Reasonable size, it would not rubs against your legs while riding. C. Reflective trim on both sides of bags to keep your night ride safety. D. Slim body design with high capacity to minimize the wind resistance.