I went with a flip folder by BAK, the MX4. It seems to set lower than most, to the bed, giving a cleaner look. Two nuts hold it in place at the front, then 3 pair of latch's on the panels themselves, that are activated by a pull cord inside the bed. When the tailgate is closed and locked the pull cord is unacceptable, making it reasonably secure. The panels are Aluminum, with a 400lb rating across the span, so they cannot simply be cut with a knife. Seemed to do a good job keeping the inside dry with the 3/4 inches of rain we got last night.
