[LARGE CAPACITY]: The Bike saddle bag with bucket bag, expand space from 0.8L to 1.3L. It’s perfect for a tool kit, an inner tube, a snack or two, and sometimes your phone& keys. Besides, double zipper linkage design, easy to open and close with winter gloves. [DOUBLE FIXING]: A saddle bag that doesn't move! Those cheap nylon straps and/or buckles on most other saddle bags just wouldn't stay in place. This saddle bag is locked down by adjustable straps and brackets. Attention to fit 4-5.3cm (1.57-2.09inch) seat rail width. [EXPLICIT PARTITION]: Our bike bag has multiple built-in mesh pockets to make it easy for you to categorize and store your items. You can put your small items in different areas. [WATERPROOF]: The ROCKBROS bike bag is made of polyester and PU fabric. Waterproof fabric with Gluing zippers for rain. Do not immerse the bag in water for a long time (Stitches are not waterproof). [REFLECTIVE DETAIL]:The bike seat bag has multiple reflective markings for night riding. You can also install a taillight for added safety when riding at night (TAILLIGHT NOT INCLUDED).