Health What is the most secure truck bed cover? What is the most secure truck bed cover? Painted one-piece tonneau covers are the most secure covers on the market. Their anti-theft design locks in a position that overlaps the tailgate, and the tailgate can only be opened if the cover is unlocked and in the upright position. Related Posts:Is Gator covers legit?Which is better Roll n Lock or Retrax?Bed Bug Killer with Egg Kill is ready-to-use.Are truck bed covers worth it?