I had a quad fold on my long bed, but as I get older (74 and still counting) is was getting harder and heavier to fold and lift it into the stowed position for towing.
The kids gave me a Pace Edwards Jackrabbit retracting cover for Christmas. I should have asked for it years ago.
Fit is perfect without shims and it installed exactly as the instructions specified. Half hour job after the old cover was removed.
Manual retract and extend. One hand operation. Locks at each one foot stop along the bed. My son and I built a bulkhead across the box at the second stop and I now have a lockable truck box even with the trailer hitched up.
Love it!