Attaches to the rear of air cleaners on Peterbilt 379 models. Available for both standard or premium air cleaners. In order to properly install the lite bars, check whether your air cleaner has a standard or premium can. If unsure check where the cover meets the can, if there is a flange, you have a STANDARD CAN, if it is flat with no flange, you have a PREMIUM CAN. Lites are red, but are available in both a clear lens and red lens.