Thule Rapid Crossroad Foot Pack Designed exclusively for use the the Rapid Aero aluminum load bars, (sold seperately) Maximum rack strength and custom fit provided by rubber coasted steel strap Easy to install with the turn of the handle One Key System- can be locked with four lock cylinders. For aeroblade cut under bar cover strips to fit between outside of foot and inside of endcap Refer to Fit guide for recommended bar length and application Strips should cover endcap retention tab. Press carefully into place, slide tab on smartslides up against feet