Large storage space: this bike bag is large enough to store your tools and necessary items, while sitting compactly under the frame. It includes a dedicated pocket for a mobile phone, headphones, and money clip, plus a large mesh pocket for keys, nutrition, and more. Reflective trim for visibility: a reflective strip enhances safety for night riding, helping you stay seen. Easy to install: three adjustable Velcro straps secure the bag to the tube, keeping it in place on bumpy or rocky roads. It fits most mountain bikes, racing bikes, and commuter bikes. Slim yet abundant: the bag is barely wider than the top tube, so it won’t rub your legs and can reduce wind resistance. It is suitable for storing keys, phone, ID, first aid kit, flat tire kit, bicycle tool, chapstick, or a small snack. Use scenarios: - Daily commute: keep your phone, ID, and money clip within easy reach; use the mesh pocket for keys and a snack. - Long-distance rides: carry a compact repair kit, tire kit, and tools without bulk. - Night rides: the reflective strip adds an extra layer of visibility for safer travel.