I sell tonneau covers.
RollNLock and Retrax are good products. I don't particularly like BAK products. Some folks like Pace Edwards retractables (Jack Rabbit and Full Metal Jacket), but I hear of some having problems with them after a while.
RollNLock is vinyl covered aluminum. The only risk is thatsomeone could cut thevinyl, although they could not penetrate the aluminum. Retrax is made of Lexan, a materialoften used in the airline industry.The roll up cannister is a little larger than RollNLock's cannister. Again,both RollNLock and Retrax aregood and they are about the same price, you'll be happy with either. Let me know if you have any questions.
RollNLock:
http://img.photobucket.com/albums/v4.../RollNL100.jpg
http://img.photobucket.com/albums/v4.../RollNL101.jpg
Retrax:
http://img.photobucket.com/albums/v4.../Retrax101.jpg
http://img.photobucket.com/albums/v4.../Retrax103.jpg