Ford F-150 2010 Owner's Manual page 121

Note: When replacing a cleat into the rail, make sure the oval embossed
on the knob is not upside down. This will ensure that the cleat is
properly oriented to accept accessory attachments.
Front header bar: Spans the header area of the pickup box, providing
the function of a header rail.
• Attachment cleats from side rails or other attachments may be
positioned in the front header bar to secure loads up to 600 lb
(272 kg) per cleat (maximum of two cleats).
• Cleats and other attachments may be inserted through the access
window located in the center of the header bar. These items can then
be slid to either side, and secured the same way as the side rails.
Driver Controls
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