are where the factory channels were once attached. They tend to take abuse from road debris and such, so they probably got ripped off at one point. Or they were chewed up so someone finished removing them. Anyway, I bought new OEM Liners because mine are a bit rough. Weren't expensive....maybe around 50 bucks each. I'm going to put the additional CZP Louvers since I'm upgrading IC's and adding foglight ducts which will direct air to the IC's. I figure the new air I'll be introducing through the area will need a larger exit. GPA