From its retractable function, which permits opening or closing in literally seconds, to its rigid, vinyl-over-aluminum laminated construction, the Roll-N-Lock M-Series 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 crossbars to negotiate, no fabric shrinkage to struggle with, no folding or solid hinged covers to combat, and, best of all, no worries about the security of cargo. What sets Roll-N-Lock's M-Series tonneau cover construction apart from the competition is not just the superior quality of our vinyl surface material, but also the design of the slatted aluminum substrate which supports the vinyl. Each Roll-N-Lock slat is rotatively joined by an interlocking hinge. It is the geometry of this uniquely-contoured hinge that lends Roll-N-Lock tonneau covers their strength, quiet, smooth, non-binding movement and roll compactness. Close examination of the Roll-N-Lock hinge in the flat position reveals the fact that each slat is inseparably locked together, yet when rotated, no metal-to-metal contact occurs.