2014-2018 Silverado Roll-N-Lock M-Series Tonneau Cover (LG222M)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 not. There are no snaps to manipulate, there is no roll or bundle to lash down or stow, no cross bars to negotiate, no fabric shrinkage to