Those that upgrade their suspension will understand when we say that fender liner components tend to vanish out of thin air. ECS Tuning has gathered all the parts needed to keep that liner in place.
Without the correct bits in place, your fender liners can simply come off and allow debris into your wheel housing, damaging the metal.
Don't drive around with a loose liner if you have lost yours though. Keep it tight with a set of new fender liner hardware. All of the correct fasteners for each one of your holes in the fender liner.