Trail Armor's nerf sliders for the Polaris RZR4 800 are made of high density 1/2" uhmw polymer. Because they are made of plastic, they are lighter than typical metal skids, and absorb the shock of impact - no dents and rust. This two piece set bolts up tight to the vehicle's bottom and does not hang down to get caught on obstacles. It protects from wheel well to wheel well, rolling up the sides to safeguard the plastic rocker panels. Strategically placed drain holes allow dirt and debris to wash out for drainage and easy cleaning. Mounts easily in factory pre-drilled holes. Trail Armor's center skids for the RZR4 (shown spanning vehicle center front to rear in pictures) are sold separately. Slider nerfs consist of left and right side panels only.