As handy as could be, Marker's Kingpin Brakes automatically lock into place when you switch your Kingpin Bindings into walk mode, and then cleverly switch themselves back into downhill mode when you're ready to rip. They are super easy to replace and come in two sizes - pick the 100mm brakes for 75mm-100mm ski waist widths and pick the 125mm brakes for 100mm-125mm ski waist widths.