★ DURABLE AND WATERPROOF: The bag's surface is made of microfiber cloth and 900D nylon, which is soft, wear-resistant, water-repellent/can withstand heavy rain, dustproof, durable, has high strength, and is easy to clean. The orange lining inside is also made of polyester. ★ SECURE WITH FOUR VELCRO STRAPS: The bag is attached with four Velcro straps: two on the seat post and two on the saddle rails. All Velcro straps are adjustable. The required seat post diameter is less than 4 cm. ★ REFLECTIVE ELEMENTS AND TAILLIGHT HOLE: There is a hole under the water bottle pocket to attach a taillight. This improves your safety while cycling. The bag has an inner pocket for your water bottle. (Taillight and bottle not included) ★ INTERNAL STRUCTURE: An opening in the lining allows you to insert items, there is a mesh pocket under the opening, a small mesh pocket on the side, a small pocket on the other side, and an elastic band to secure your belongings. ★ Size: 24 x 8.5 x 8.2 cm; Weight: 0.2 kg; Large capacity: approx. 1.6L; The zipper seams are flat and waterproof, making the bag waterproof. Note: The zipper style has been improved, and the star shape has been replaced with a square shape. Features: Brand: ROCKBROS Model: C7-1 Material: Microfiber Size: approx. 24*9.6*10.5cm Position: Saddle Package includes: One bag Waterproof: Microfiber material. Taillight mount and reflective elements. Large capacity: 2.5L. Suitable for city bikes, mountain bikes, road bikes, etc. Waterproof. The bag's surface is made of lightweight, rain-resistant polyester. Taillight mount design. Note: package does not include taillight or water bottle! Inner pocket. The mesh pocket inside allows for separate storage. Zipper. Two zippers slide smoothly.