Sliders or rock rails are critical to protection of the rocker panels of the Toyota FJ cruiser. When dropping over ledges of going over large rocks the break over angle forces the rocker panel of the FJ on to the obstacle. The rock sliders are attached to a strong frame mounted surface and will both take the impact and allow the FJ to “slide” over obstacle with out sustaining any body damage. Some rock rails extend beyond the body providing additional protection to the side panels of the FJ as well as providing a step for roof access. If you are modifying your FJ for off-road use I highly recommend that rock rails be one of your early modifications.
There are a number of manufactures the build high quality rock rails or sliders. The features you want will direct you to specific vendors.
Note that Rock Rails are not attached to the body!!! Some after market modifications are not real rock rails and the use a body mount.