Roll N Lock M-Series Truck Bed Cover for 04-06 Chevy Silverado/GMC Sierra 1500 Crew Cab 5.8 Ft. Bed Model LG270MRoll N Lock M Series Locking Retractable Truck Bed Cover for 2004 2006 Chevrolet Silverado GMC Sierra 1500 Crew Cab 5. 8 Ft. Bed Model LG270M Roll N Lock M Series is the most advanced retractable truck bed cover made, has redefined the rules for truck bed security. From its retractable function, which permits opening or closing in seconds, to its rigid, vinyl over aluminum laminated construction, this hybrid cover offers everything other covers do