Drop-in plastic liners require drilling holes in the truck bed to secure the liner to your truck and will shift or vibrate over time damaging your bed’s finish. The Black Armour® mat uses non-abrasive rubber which will not scratch the finish of your truck and installation does not require any drilling holes. Drop-in liners are not only rough on your cargo, but they are also rough on your knees when climbing in to access it. Black Armour® mats provide a joint-friendly ½” rubber surface when you need to climb inside your truck bed. The Black Armour® mat will not fit with a plastic liner installed. You must remove the plastic liner before installing a Black Armour® mat.