Elecday MTB Bicycle Bike V-Brake / Cantilever Brake Booster ,Black For bikes w/ v-brake and cantilever brake system Stiffen seat stay or fork boss improving brake performance Gives a crisp feel to your rear V or cantilever brakes by reinforcing your rear triangle Mounting hardware and standoffs are included Dimension: Approx. 5.2 x 4.5 inch / 13.2 x 11.4cm