ENGINEERED FOR THE PERFECT FOLD: Stop removing your gear every time you hop on the train. This bag fits precisely within the frame triangle of Brompton bikes. Its slim profile ensures it never interferes with the folding mechanism, allowing you to fold, roll, and carry your bike with the bag securely attached. UPGRADED 3.0 STABILITY SYSTEM: We listened to rider feedback. The new Boomerang 3.0 features Anti-Slip Straps and a discreet integrated magnet on top. These upgrades lock the bag against the frame tube, preventing the annoying swaying or sliding common with standard velcro bags. MAXIMIZE "DEAD SPACE" STORAGE: Utilize the unused space on your frame. This pouch is the ideal size for carrying ride essentials that usually clutter your pockets—a spare inner tube, multi-tool, tire levers, energy gels, or your house keys. It keeps your center of gravity low and your pockets empty. HIGH-VISIBILITY ORGANIZATION: No more digging into a black hole. The interior features a bright contrast lining that makes finding small black screws or tools easy, even in low light. Includes an internal mesh pocket to keep cash, cards, or coins separate from greasy bike tools. DETACHABLE "GRAB-AND-GO" DESIGN: Need to pop into a shop? The hook-and-loop straps are fully detachable, allowing you to instantly strip the bag from the bike and use it as a standalone coin pouch or wallet. It’s versatile, portable, and built for the urban commuter. The Brompton is a marvel of engineering, but it lacks convenient storage for the small things. You don't always want to mount a massive front carrier block bag just to carry a repair kit and your keys. The Vincita Boomerang Bag 3.0 is designed to live on your bike. Shaped to fit perfectly into the frame's front triangle, it utilizes "dead space" to store your essentials without affecting the bike's iconic folding capability. Previous frame bags had a tendency to slide or sway while pedaling. We have completely overhauled the mounting system: The slim profile ensures your knees never brush against the bag while riding. Inside, the Bright Orange Lining ensures you can actually see your gear, while the internal mesh pocket keeps your credit card or cash secure. Spare Inner Tubes (16") Mini-Tools & Patch Kits Keys & Wallets Energy Bars Specifically tailored for Brompton C Line and P Line frames. (Also fits pre-2022 standard steel frames).