Defender M1 is compatable with all standard front forks including reverse arch designs. The unique quick release attachment system integrates the M1 seamlessly with the front of your bike. The 2 pivot arm of the M2 articulates for enhanced coverage & a perfect bike fit. A stiff engineering grade plastic support frame is co-moulded to a softer & more flexible material at the trailing edge for greater durability. Two-tone injection-moulded nylon construction Quick release for front & rear Seatpost clamp fits 25.4mm to 34.9mm Lightweight: 190g Front & 230g Rear