Before you add your drop-in bed liner for the full protection protect the bed of your truck from the wear and tear of a rigid bed liner rubbing against the painted surface. WeatherTech’s UnderLiner is digitally designed to perfectly match the contours of your specific pickup truck bed. It provides added protection by creating a .065" thick semi-soft protective barrier between the rigid drop-in bed liner and the painted surface of your truck bed. The UnderLiner is designed for placement under a rigid drop-in truck bed liner only. Do not use or secure without a bed liner.