The Pendaliner SR gives you twice the protection of ordinary bedliners! Its skid-resistant top helps protect your cargo by reducing cargo movement. And its skid-resistant bottom helps protect your truck bed by reducing bedliner movement. You get double the protection with Pendliner SR! If you don't intend to install additional truck accessories and if extra loading flexibility is not a concern, you may prefer the smooth finished look of the Pendaliner SR over the over-railmodel. This model also provides extra rail protection and compartmental loading.